British Journal of Urology (1998), 82, 548–551

The long-term eVects of prostatic infarction in the ratM.S. PARK, A. LEE and S.E. LE E*Department of Urology, Seoul Municipal Boramae Hospital and *Seoul National University College of Medicine, Seoul, Korea

Objective To evaluate the long-term eCects of infarction, Results The size and mean (sd) weight of the treatedlobes decreased markedly, to 148 (34) mg, comparedwhich usually induces organ atrophy, on the prostate

by examining the changes occurring in rat ventral with those of the controls, at 698 (62) mg (P<0.01).The treated lobes were composed of both normal andprostate after infarction.

Materials and methods The unilateral arteriolar atrophic glandular tissue.Conclusion Prostatic atrophy can be induced by infarc-branches to the ventral prostate were electrocauterized

under an operative microscope in 10 adult rats. The tion in the rat; prostatic infarction might have poten-tial as a new therapeutic strategy in the treatment ofgross and histological changes of the treated lobes of

the ventral prostate were compared with those of benign prostatic hyperplasia.Keywords Infarction, prostate, rat, atrophyuntreated control lobes in the same rats 12 weeks

later.

tion with 0.1 mg ketamine. The peritoneum overlyingIntroductionthe bladder and prostate was incised with microscissorsunder an operative microscope, through a midlineIn contrast to prostatic cancer, BPH is a common

disease in both Western and Asian countries [1]. TURP incision. After the ventral prostate was dissected carefullyfrom the bladder, the ventral arteriolar branches fromremains the ‘gold standard’ for the treatment of BPH,

but it has significant morbidity. Unfortunately, current the periurethral circle of vessels supplying the ventralprostate were easily identified at the junction betweenpharmacological and minimally invasive treatments for

BPH are not as eCective as TURP, and thus more the bladder and the ventral prostate. All branches supply-ing one lobe of the ventral prostate were electrocauterizedeCective and less invasive treatments for BPH must be

developed. with bipolar electrodes. The treated lobe of the ventralprostate immediately became pale, in contrast to theThe target of current minimally invasive treatments

for BPH is mainly the prostatic parenchyma [2,3], but contralateral lobe which remained pink. The wound wasclosed with a 2–0 silk continuous suture. The experimentwe propose that treating the supplying vessels rather

than the prostatic parenchyma directly may be more was designed to cause infarction of one lobe so that theanimals acted as their own controls.eCective. Infarction induces atrophy of aCected organs,

and arterial embolization is currently used in the treat- After 12 weeks the rats were prepared using the samemethods and both lobes of the ventral prostate removed.ment of liver, kidney and bone tumours [4]. Recent

developments in colour Doppler ultrasonography have After weighing and measuring each lobe, they were fixedin formalin, paraBn-embedded, sectioned at 5 mm andallowed the imaging of the vascular system of the

prostate [5]; with this information, the vessels could stained with haematoxylin and eosin. The gross andlight microscopic appearance of the treated and thethen be ablated by current therapeutic devices used to

treat BPH. Thus we examined the long-term eCect of control lobes were compared.prostatic infarction in the rat, to evaluate the possibleuse of prostatic infarction as a new therapeutic strategy Resultsin the treatment of BPH.

The size of the treated lobe decreased markedly comparedwith the contralateral (control) lobe of the ventral pros-Materials and methodstate 12 weeks after infarction (Fig. 1). The mean (sd)weight of the treated lobes was 148 (34) mg, significantlyTen male adult Sprague Dawley rats (body weight

#300 g) were anaesthetized by an intraperitoneal injec- lower than that of the controls, at 698 (62) mg(Wilcoxon signed-ranks test, P<0.05). Microscopically,the treated lobes of the ventral prostate were composedAccepted for publication 10 June 1998

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LONG-TERM EFFECTS OF PROSTATIC INFARCTION 549

Fig. 1. The ventral prostate and the bladder of the rat afterunilateral infarction. The size of the treated lobe (white arrow)decreased markedly compared with the contralateral lobe.

of both normal and atrophic glandular tissues. Largefoamy cells were frequent in the epithelium of theatrophic ducts adjacent to the normal ducts (Fig. 2).

Discussion

a

b

c

Fig. 2. Histological sections of rat ventral prostate after infarction,Complete infarction inevitably results in atrophy of the showing both normal and atrophic glandular tissue. a, The normalorgans; testicular atrophy results from infarction [6] and ducts are lined with tall columnar secretory epithelial cells. Thenearly all angiomyogenic components of renal angiomy- blood vessels were filled with viable erythrocytes. b, A single layer

of flat cells line the atrophic ducts. c, Large cells with foamyolipoma disappear after selective embolization [7]. Recentcytoplasm and pyknotic nucleus scattered in the flat to cuboidalstudies show that ischaemia induces apoptosis of theepithelium of the atrophic ducts. The blood vessels (white arrows)aCected cells [8,9]; the prostate should be no exceptionwere occluded by hyalinized erythrocytes and haemosiderin

to this eCect and the present results confirm this hypoth-pigmentation. Haematoxylin and eosin. Original ×200.

esis in the rat prostate model.The treated lobes in the present study decreased

markedly in size, but they were composed both of normaland atrophic glandular tissue. The ventral lobe of therat prostate is supplied by two vascular systems, one

© 1998 British Journal of Urology 82, 548–551

550 M.S. PARK et al.

supplying the median two-thirds of the ventral lobe and [17] reported that prolonged operative hypotension wasassociated with acute prostatic infarction. However, thethe remaining external third supplied by the pericapsular

branches of the fat pads [10]. In this study, only the cause and eCect relationships between prostatic infarc-tion and acute urinary retention are unclear; the acuteventral branches emerging from the periurethral circle

were cauterized; thus the histological eCects probably changes caused by prostatic infarction should beevaluated.arose from atrophy of the median two-thirds of the

ventral lobe after infarction, whereas the external third In conclusion, the present study illustrates the possibil-ity of using prostatic infarction as a new therapeuticof the ventral lobe, supplied from the pericapsular fat

pads, was preserved. strategy for treating BPH; more research of this potentialmethod is warranted.The foamy cells found in the treated lobe of the ventral

prostate seem to arise during the process of ischaemicnecrosis, because they were located between flat tocuboidal epithelium of the atrophic ducts adjacent to the Referencesnormal ducts. They have not been described previously

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© 1998 British Journal of Urology 82, 548–551