IJEES 03|Volume 1|Issue 1|2015
The International Journal of Earth & Environmental Sciences
Research Article
Salient Alterations in Hepatic and Renal Histomorphology of an Indian Minor Carp, Labeo bata (Hamilton, 1822) Owing to ZnS Nanoparticle Induced Hypoxia and Environmental Acidification
Nilanjana Chatterjee1, Baibaswata Bhattacharjee
2
1Department of Zoology, Ramananda College, Bishnupur-722122, Bankura, India
2Department of Physics, Ramananda College, Bishnupur-722122, Bankura, India
Correspondence should be addressed to Baibaswata Bhattacharjee
Received May 18, 2015; Accepted July 03, 2015; Published July 06, 2015; Copyright: © 2015 Nilanjana Chatterjee et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
ABSTRACT Due to enhanced surface photo-oxidation property of ZnS in its nanoparticle form, the dissolved oxygen content and pH value of water was found to reduce in a dose dependent manner from their normal values, when ZnS nanoparticles of different sizes are exposed to the water in various concentrations. This property was more prominent for ZnS nanoparticles with smaller sizes. Labeo bata, exposed to ZnS nanoparticles, responded to hypoxia with varied behavioural, physiological and cellular responses in order to maintain homeostasis and organ function in an oxygen-depleted environment. Due to the minimization of food uptake, the hepatic cells of L. bata were found to shrink and empty spaces generated in between them as they used storage deposit to maintain the metabolic activity of the fish. The kidneys of the exposed fishes showed shrinkage of glomerulus and dilution of tubular lumen due to reduction in glomerular filtration rate in oxygen depleted atmosphere. Vacuolization and hyaline degeneration of tubular epithelium were also seen in the renal histomorphology of L. bata when the exposure time exceeded 6 days.
KEY WORDS: ZnS nanoparticles; Photo-oxidation; Hepatocytes; Renal histomorphology; Morphometry
INTRODUCTION
Snowballing of nanotechnology and mounting uses of
nanoparticles in sundry fields of sciences [1-3] have
increased considerably the probability that the
nanoparticles would end up in water courses either as
chemical, medical, industrial or domestic wastes. ZnS
nanoparticles (NPs) are one of such materials that can be
found in the wastes of cosmetic, pharmaceutical and
rubber industries. Apart from the various physiological
disorders due to direct uptake of nanoparticles by the
aquatic animals through different parts of their body [4-
10], ZnS nanoparticles are expected to exhibit some
passive effects on aquatic environment by changing
important physicochemical parameters of water due to its
property of surface photo-oxidation [11]. Due to enhanced
surface photo-oxidation property of ZnS in its
nanoparticle form, the dissolved oxygen content in water
is found to reduce in a dose dependent manner from their
normal values, when ZnS nanoparticles of different sizes
are exposed to the water in various concentrations [8, 11-
12]. This property is more prominent for ZnS
nanoparticles with smaller sizes. Consequently under the
exposure of ZnS NPs, the aquatic fauna of that
Open Access Scientific Publisher www.advancejournals.org
Cite This Article: Chatterjee, N., Bhattacharjee, B. (2015). Salient alterations in hepatic and renal histomorphology of an Indian
minor carp, Labeo bata (Hamilton, 1822) owing to ZnS nanoparticle induced hypoxia and environmental acidification. The
International Journal of Earth & Enviromental Sciences 1(1). 1-9
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The International Journal of Earth & Environmental Sciences
particular habitat are forced to live in an oxygen depleted
atmosphere [8, 11-12]. When living in a habitat with low
level of dissolved oxygen, fish respond to hypoxia with
varied behavioural, physiological, and cellular responses
in order to maintain homeostasis and organ function in an
oxygen-depleted environment [13-19].
Fish is one of the major sources of edible protein
in India. Therefore, its reproduction has acquired prime
importance to the investigators working in this area.
Labeo bata is a species of freshwater Indian minor carp,
found mainly in the rivers of India, Bangladesh and
Myanmar. This species is very common, easy to cultivate
and an important target species for the small-scale
fishermen. Though this fish species has a high nutritional
value in terms of protein and micronutrients, yet it is
available in a relatively cheaper price in the fish market
compared to some other fishes having equivalent
nutritional values. These reasons make L. bata a very
attractive candidate for aquaculture in the South East Asia.
The aim of our present study is to monitor
systematically the adverse effect of ZnS NPs on
histomorphology of liver and kidney of L. bata. This will
also help to realise how the growth and maturity of the
fish are being hampered when exposed to ZnS NPs. The
changing behaviour in growth and maturity of any
member of an aquatic environment due to exposure of
nanoparticles may cause an adverse effect on the aquatic
ecosystem as a whole. In the present case, it also has its
detrimental effect on the commercial market of this fish.
EXPERIMENTAL
Synthesis and characterization of ZnS nanoparticles
ZnS NPs were synthesized employing simple wet
chemical method as described by Chen et al. [20]. After
synthesis the nanoparticles were characterized through
Transmission electron microscopy (TEM), Particle size
analysis (PSA), X-ray diffraction (XRD) study, Energy
dispersive X-ray (EDX) study and X-ray photo electron
spectroscopy (XPS) study. The process of synthesis and
characterization procedures of the ZnS NPs were
described in detail elsewhere [8, 12]. Different
characterization techniques ascertained undoubtedly that
stoichiometric, spherical ZnS nanoparticles of different
sizes (3 nm, 7 nm, 12 nm and 20 nm) were acquired under
different experimental conditions of synthesis technique
[12].
Fish husbandry
Matured L. bata specimens of both sex groups
caught by means of traditional fishing gear cast net and
conical trap during daytime (10:00-15:00 hours) in
monthly basis from different places of Hooghly and
Bankura districts of West Bengal, India, were collected
from the local fishermen during the period of September,
2011 to August, 2013. Immediately after collection, fishes
were kept in watertight containers containing tap water
that has been allowed to stand for a few days. A good
supply of necessary oxygen was provided by using a large
shallow tank to ensure that a large surface area of water
was exposed to the air. Fishes were maintained at 25°-
30°C of temperature to ensure the natural environment.
The fishes were fed on natural fish foods. Small, regular
supplies of food were provided. The fishes were filtered
out in every 10 days and are placed in fresh water.
Histology and histometry
To study the hepatic and renal histology, liver
and kidney tissues were dissected out and cut into small
pieces for preservation in Bouin’s fixative for 18 hours.
The tissues were then dehydrated through ethanol,
C2H5OH (GR, Merck India) dried over activated
molecular sieve zeolite 4A, cleared in xylene and
embedded in paraffin of melting point 56°-58°C. Thin
sections of 4 µm thicknesses were cut using a rotary
microtome machine. The sections were stained with
Delafield’s Haematoxylin and Eosin stain and were
observed under a compound light microscope of high
resolution and eventually photographed with a digital
camera attached to the microscope.
The morphometry of hepatic and renal tissues
were done using reticulo micrometer and ocular
micrometer attached to the compound light microscope.
Each measurement was made four times and their mean
value was used for any analysis.
Toxicity test
Fish specimens were exposed to six
concentrations (σ = 100, 200, 250, 500, 750 and 1000
μg/L) of the ZnS nanoparticles of different sizes (3 nm, 7
nm, 12 nm and 20 nm) for 6 days. Trials were conducted
at various concentrations to observe the impact of ZnS
nanoparticles on L. bata liver and kidney, comparing the
hepatic and renal histomorphology of the exposed fishes
to that of the fishes lived in controlled conditions.
Electronic lab meters with accuracy up to one decimal
point were used to measure the dissolved oxygen content
and pH of the water.
Statistical analysis
All data were expressed as means ± SE. One-way
analysis of variance was run to compare the differences
between groups treated under different experimental
conditions and control groups. Differences were
considered statistically significant when p < 0.05.
Pearson’s correlation coefficients (r) were calculated to
determine the correlation, if any, between different hepatic
and renal morphometric parameters and nanoparticle
concentrations and exposure times at a significance level
of 5%. Negative r values prefixed by negative (-) sign and
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positive values without any prefix are used in the
manuscript. Curve fitting to the experimentally obtained
data was done using the software Origin 9.
RESULTS AND DISCUSSIONS
ZnS NP induced hypoxia and environmental
acidification
In the present study, the dissolved oxygen
content in water (DO2) was measured to be 13.2 mg/L at
15°C before any nanoparticle was introduced in it. This
value was found to decrease both with increasing
nanoparticle concentration as well as nanoparticle
exposure time in water at the same temperature. The value
of dissolved oxygen content in water reached to as low as
3.9 mg/L for nanoparticles of size 3 nm at a concentration
of 1000 μg/L and exposure time of 6 days.
The photo-oxidation of the surface of ZnS NPs
using the dissolved oxygen of water under sunlight and
consequent reduction of dissolved oxygen content in water
has been confirmed from detailed study of S 2p core level
X ray photoelectron spectra of ZnS nanoparticles after
different time of exposures [12]. During the surface photo-
oxidation process of ZnS NPs, The S atoms exposed to the
ZnS surface got oxidized and an increase in concentration
of chemisorbed SO2 at ZnS surface with increasing
exposure time was observed in the samples [12]. The
oxide leaves the surface as a molecular species (SO2),
leaving Zn and a freshly exposed layer of ZnS behind.
Water may dissolve a part of the SO2 released in the
process causing reduction in the pH value of the water
[11]. Subsequently under the exposure of ZnS NPs, the
aquatic fauna of that particular habitat were forced to live
in an oxygen depleted and acidified atmosphere [8, 11-
12].
In the present study, the pH value of water was
found to decrease when exposed to ZnS NPs in a dose
dependent manner for a fixed exposure time of 6 days. In
controlled condition the pH value of the water used in this
experiment was measured to be 7.6. This value was found
to decrease both with increasing nanoparticle
concentration as well as nanoparticle exposure time in
water for a fixed nanoparticle size. The rate of reduction
in pH value was found to be higher for the nanoparticles
with smaller sizes. In our experiment, the pH value of
water dwindled down to 4.8 for nanoparticle concentration
(σ) of 1000 μg/L with size (d) 3 nm and exposure time (t)
of 6 days. Reduction of water pH and consequent
acidification of the environment finally lead the fishes to
metabolic acidosis.
After the exposure of the ZnS NPs in the water,
the Zn/S ratio in the nanoparticles was found to rise over
that of the stoichiometric value of the freshly prepared
samples confirming the loss of S from the surface of the
nanoparticles. Surfaces of the ZnS NPs, exposed to water
and light, were thus effectively destroyed by the redox
cycles and resulted in the reduction of the dissolved
oxygen content and pH value of water. This property was
found to be more prominent for ZnS NPs with smaller
sizes. This observation could be explained by the fact that
smaller particle size culminated higher surface to volume
ratio of the nanoparticles present in the water. Therefore,
ZnS NPs having smaller sizes offered greater surface area,
making the particles more sensitive to surface photo-
oxidation process. This lead to a faster deficit in dissolved
oxygen content and reduction in pH values when exposed
to water compared to the samples having larger particle
sizes.
Hepatic histology
The liver cell structure of teleosts responds very
sensitively to environmental changes, e.g. in temperature,
season, feeding conditions or presence of various
chemicals in the water [21]. Therefore, liver histology can
be used as an indicator to show the harmful effect of ZnS
NPs on L. bata. Figure 1(a) shows the in situ position of
liver in a female L. bata.
Figure 1 (b) shows the histomorphology of L.
bata liver in controlled condition portraying the liver cells
in normal and healthy states. In this figure, liver cells are
found to be large with regular outlines. These cells are
dominated by storage deposits. The nuclei are found to be
large and centrally located indicating the normal condition
of the cells. The cells are found to be in close contact,
almost no empty space is found between the cells.
Figures 1(c)-1(e) show the effect of increasing
nanoparticle concentration on the liver histology of L.
bata. For exposure to ZnS concentration of 100µg/L
(Figure 1c), few cells are found to be in degenerating
states without a prominent nucleus and having diffused
cytoplasmic contents. For higher concentration of ZnS
nanoparticles (σ = 500 μg/L), decrease in cell sizes due to
drastic loss of storage deposits is observed (Figure 1d).
Therefore, the relative share of nucleus in cell volume is
strongly increased. The cells are found to be in increasing
isolated states having no close contact between them
(Figure 1d). Under high concentration exposure (σ = 1000
μg/L) of smaller ZnS nanoparticles (d = 3 nm), some of
the fish livers also show disruption of hepatic cell cords
and apoptotic changes such as chromatin condensation
and pyknosis as indicated by arrows in figures (Figure 1e).
The histological alterations are more pronounced for
exposure to nanoparticles of smaller sizes. This
observation can be associated with the increasing surface
reactivity of the nanoparticles with decreasing size. The
observation is similar for male L. bata.
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Figure 1: (a) Exposed thoracic and abdominal cavity of the female Labeo bata, showing the position of liver in situ in
the thoracic region. Photomicrographs showing the liver histology of female L. bata under (b) controlled condition, (c)
exposure to ZnS NP concentration of σ = 100 μg/L for 6 days, d = 3 nm, (d) exposure to ZnS NP concentration of σ =
500 μg/L for 6 days, d = 3 nm and (e) exposure to ZnS NP concentration of σ = 1000 μg/L for 6 days, d = 3 nm. In this
case, livers tissues showed disruption of hepatic cell cords and apoptotic changes such as chromatin condensation and
pyknosis as indicated by green block arrows in figure. [hepatocytes (hc), fat vacuoles (fv-white block arrows), blood
vessels (Bv), empty space generated due to apoptosis ( ) and blood cells (Bc)].
4
200 μm 200 μm
200 μm 200 μm
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Nanoparticle
size (d) (nm)
δ0 (μm) α (μm) τ (μg/L) Reduced
χ2
3 9.380 11.103 167.134 1.540
7 10.060 10.296 211.027 1.405
12 14.247 6.138 237.224 0.438
20 14.564 5.798 355.829 0.275
Hepatic morphometry
Figure 2: Variation of the hepatic cell diameters (δ)
against increasing nanoparticle concentrations (σ) with
correspondingly fitted first order exponential decay
curves for nanoparticles of different sizes (d) having fixed
exposure time (t) of 6 days in female L. bata
Figure 2 shows the change in the values hepatic
cell diameter (δ) for female fishes with increasing
nanoparticle concentration (σ) for nanoparticles of
different sizes (d) used, when the exposure time is fixed (t
= 6 days). δ values are found to decrease with increase in
σ value up to 500μg/L for every size of the nanoparticles
(d) used and a fixed (t = 6 days) exposure time. Beyond
this concentration, this value remains nearly constant.
Strong negative correlation (r = - 0.798) is obtained
between δ and σ for constant d (3 nm) and t (6 days).
Analysis of covariance reveals significant differences
between the δ values (p < 0.001) for nanoparticle
exposures of different concentrations.
A significant negative correlation (r = - 0.902) is
revealed between NP exposure time and hepatosite sizes
(σ = 500 μg/L, d = 3 nm) during the toxicity test. Also a
significant negative correlation (r = - 0.843) can be
demonstrated between exposure time and hepatosite
density for a fixed nanoparticle concentration (σ = 500
μg/L, d = 3 nm). The percentage of empty space in the
hepatic tissue lay out is found to increase (r = 0.712) with
increasing exposure time for a fixed concentration of ZnS
NP (σ = 500 μg/L, d = 3 nm). These observations become
more prominent with decreasing nanoparticle sizes.
Similar type of qualitative variation is found in liver
histomorphology of male L. bata.
Data presented in figure 2 are fitted well to the
first order exponential decay curves represented by the
following equation
⁄
where δ0, α and τ were the fitting parameters for the
family of curves shown in figure 2. δ0 corresponded to the
extrapolated value of hepatic cell diameter (δ) if the
nanoparticle concentration (σ) reached infinity. The
inverse of τ values determined the slopes of the fitted
curves. Table I portrays the fitting parameters for the
curves depicting the changes in the values of hepatic cell
diameter (δ) with increasing nanoparticle concentration
(σ) for nanoparticles of different sizes (d) having fixed
exposure time of 6 days in female L. bata. From the slope
of the curves, it can be established undoubtedly that the
detrimental effect was stronger for particles with smaller
sizes.
Table I
Fitting parameters for the curves depicting the changes in
the values of hepatic cell diameter (δ) with increasing
nanoparticle concentration (σ) for nanoparticles of
different sizes (d) having fixed exposure time of 6 days in
female L. bata
These observations of alterations in hepatic
histomorphology are indicative of degradation of liver
cells under nanoparticle exposure. It has been reported
that hypoxia can induce varied behavioural, physiological,
and cellular responses among fishes [13-19]. Asian dwarf
striped catfish Mystus vittatus is found to minimize their
food intake when exposed to ZnS NP induced hypoxia
[12]. Similar pattern of altered feeding behaviour can be
noticed in L. bata in the present study. Due to the
minimization of food intake under nanoparticle exposure,
the hepatic cells of the fish are found to shrink and empty
spaces generated in between them as they use the storage
in the hepatocytes and fat vacuoles to maintain the
metabolic activities in this adverse condition. These
effects can be associated directly with the changing
feeding behaviour, which in turn made a detrimental effect
on growth, maturity and spawning of the fish.
Renal histomorphology
The kidney is a complex organ made up of
thousands of repeating units called nephrons, each with
the structure of a bent tube. Blood pressure forces the fluid
in blood to pass a filter, called the glomerulus, situated at
the top of each nephron. In L. bata two elongated kidneys
0 200 400 600 800 1000 12008
10
12
14
16
18
20
22
Hep
ato
cyte
dia
metr
e ()
(m
)
ZnS NP concentration () (g/L)
3 nm
7 nm
12 nm
20 nm
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Figure 3: (a) Exposed thoracic and abdominal cavity of the female Labeo bata, showing the position of kidney in situ in
the abdominal region. Photomicrographs showing the renal histology of female L. bata under (b) controlled condition,
(c) for exposure to ZnS NP concentration of σ= 100 μg/L, (d) for exposure to ZnS NP concentration of σ= 500 μg/L and
(e) for exposure to ZnS NP concentration of σ= 1000 μg/L [glomerulus (yellow arrow), Bowman’s capsule (Bc) and
collecting tubules (ct)].
are of mesonephric type. Figure 3(a) shows the position of
the kidneys in female L. bata. Figures 3(b)-3(e) show the
renal histomorphology of L. bata under exposure of ZnS
NPs of different concentrations having size (d) of 3 nm for
fixed exposure time (t) of 6 days. The histomorphology of
the controlled kidney tissues exhibit an ordinary pattern of
renal corpuscles (consisting of glomerulus and Bowman’s
capsule) and collecting tubules with no abnormalities in
any other part of the renal cellular lay out as shown in
figure 3(b). When the fishes are exposed to relatively
lower concentration of ZnS NPs (σ ≤ 200 μg/L), the
kidneys of the fishes show shrinkage in glomerulus and
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Nanoparticle
size (d) (nm)
D (μm) A (μm) T (μg/L) Reduced
χ2
3 49.167 48.063 500.844 0.185
7 57.468 38.327 665.272 0.492
12 59.257 36.869 911.404 0.105
20 56.990 39.477 1393.630 0.071
dilution of tubular lumen. For exposure to moderate value
of ZnS NPs (σ = 250 μg/L), significant decrease in
glomerular size (p < 0.001) and density (p < 0.001) are
observed in the renal tissues of the exposed fishes (Fig.
3c) compared to that of the controlled fish. For exposure
to relatively higher concentration of ZnS NPs (σ = 500
μg/L), significant decrease in the number density
(p<0.001) of collecting tubules was noticed in addition to
the previous observations (Fig. 3d). Exposure to even
higher concentration of ZnS NPs (σ ≥ 750μg/L), results in
vacuolization in renal cell lay out and hyaline
degeneration of tubular epithelium. After exposure to the
highest ZnS NP concentration (σ = 1000 μg/L) used in the
experiment, necrosis and dispersed inter renal cells with
pyknosis of some nuclei are observed (Fig. 3e) in L. Bata.
Renal morphometry
Figure 4 shows the change in the values
glomerular diameter (D) for female fishes with increasing
nanoparticle concentration (σ) for nanoparticles of
different sizes (d) used, when the exposure time is fixed (t
= 6 days). D values are found to decrease gradually with
increase in σ values within the experimental limit for
every size of the nanoparticles (d) used and for a fixed
exposure time (t = 6 days). Strong negative correlation (r
= -0.892) was obtained between D and σ for constant d (3
nm) and t (6 days). Analysis of covariance reveals
significant differences between the D values (p < 0.001)
for nanoparticle exposures of different concentrations.
Figure 4: Variation of the glomerular diameters (D) with
increasing nanoparticle concentrations (σ) with
correspondingly fitted first order exponential decay
curves for nanoparticles of different sizes (d) having fixed
exposure time (t) of 6 days in female L. bata.
A significant negative correlation (r = - 0.882) is
revealed between NP exposure time and glomerulus size
during the toxicity test, but no significant correlation can
be demonstrated between exposure time and glomerulus
density for fixed nanoparticle concentration. The lumen
diameter of the collecting tubules is found to decrease (r =
- 0.704) and increase in muscular wall thickness (r =
0.801) is observed with increasing exposure time for a
fixed concentration of ZnS NP. Other time dependent
histomorphological alterations in renal tissues is not quite
prominent for relatively lower concentration of ZnS NPs
(σ < 500 μg/L). When the exposure time exceeds 6 days
for higher concentrations (σ ≥ 500 μg/L) of ZnS NPs,
glomerular vacuolization and hyaline degeneration of
tubular epithelium were seen in the renal histomorphology
of L. bata. Similar qualitative variation was found for
male L. bata.
Data of figure 4 are fitted well to the first order
exponential decay curves represented by the equation
⁄ Where D0, A and T are the fitting parameters as shown in
table II for the family of curves shown in figure 4. D0
corresponded to the extrapolated value of glomerular
diameter (D) if the nanoparticle concentration (σ) reached
infinity. The inverse of T values determined the slopes of
the fitted curves. From the slope of the curves, it can be
recognized indisputably that the harmful effect of ZnS
NPs was sturdier for particles with smaller sizes.
Table II
Fitting parameters for the curves depicting the changes in
the values of glomerular diameter (D) with increasing
nanoparticle concentration (σ) for nanoparticles of
different sizes (d) having fixed exposure time of 6 days in
female L. bata
Ammonia is the primary metabolic waste product
of most fishes including teleosts [22, 23]. Teleost
freshwater fishes occupy an environment that is hypotonic
relative to their tissues and, as a result, experience passive
ion loss mainly across the gills [24, 25]. As the loss of
ionic homeostasis can lead to severe metabolic
impairment [26-28], teleost fishes employ mechanisms to
actively take up ions, namely Na+ and Cl
-, by reabsorbing
ions across the nephron tubules, from the glomerular
filtrate back into the blood. In addition, they actively
transport ions across their gill surfaces from the
surrounding water into the blood.
Hofmann and Butler [29] reported that there
exists significant positive correlation between glomerular
0 200 400 600 800 1000 1200
50
60
70
80
90
100
3 nm
Glo
meru
lar d
iam
ete
r (
D)
(m
)
ZnS NP concentration () (g/L)
7 nm
12 nm
20 nm
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filtration rate and urine flow rate in rainbow trout, Salmo
gairdneri. Glomerular filtration rate also showed linear
relationship with oxygen consumption rate of the fishes.
In the present work, ZnS NP induced hypoxia forced the
fishes to lower their oxygen consumption rate for their
metabolic activities. This is supposed to reduce the
glomerular filtration rate as well as urine flow of L. bata
under exposure to ZnS NPs. This can be attributed to the
reduction in glomerular size and density of the exposed
fishes as revealed from the histological micrographs.
Acidification of the environment due to photo
oxidation of ZnS NPs resulted in the enhancement of
water H+ levels under experimental conditions. When L.
bata were exposed to this water, the existence of H+
gradient from water to blood generated the situation of
metabolic acidosis in the fishes reducing the blood pH
level. In fish, metabolic acidosis stimulates an elevation in
ammonia excretion at both the renal [30-34] and branchial
[30, 31] epithelia, presumably as a means of facilitating
acid-base regulation. Reduction in water pH had been
resulted in a significant decrease in blood pH, a large
reduction in plasma HCO3 levels, a severe impairment of
swimming ability and an increase in Na+ influx in a teleost
fish Oreochromis alcalicus grahami [35].
In the present study changes in plasma acid-base
status and ionic composition along with the oxidative
stress generated by ZnS NP induced hypoxia are supposed
to induce the altered metabolic function in L. bata. This
consequently reformed the renal activity leading to the
other salient changes in renal histomorphology.
CONCLUSION
Indian minor carp Labeo bata suffered from
salient alterations in hepatic and renal histomorphology
owing to ZnS NP induced hypoxia and environmental
acidification. Due to the minimization of food intake
under nanoparticle exposure, the hepatic cells of the fish
were found to reduce in sizes generating empty spaces in
between them as they used the storage in the hepatocytes
and fat vacuoles to maintain the metabolic activities of the
fishes in this hostile condition. Onset of metabolic
acidosis in the fishes as a consequence of the
environmental acidification due to the photo oxidation of
ZnS NPs resulted in the elevation in ammonia excretion at
the renal epithelia. Under the combined effect of
acidification and oxidative stress generated by ZnS NP in
the habitat, L. bata were supposed to induce the altered
metabolic function. As a result of this reformed the renal
activity, salient changes in renal histomorphology were
observed.
ACKNOWLEDGEMENT
The authors wish to thank the authority of
Ramananda College for providing some of the
experimental facilities.
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