animal experiments

ANIMAL EXPERIMENTS

L.NAGA KRISHNA ,

LECTARURER,

MRIMS .

HISTORICAL OVERVIEW Aristotle and erasistratus are the first to use living animals in

experiments.

Animal use in science has been developed not only in drug

discovery but also in surgical procedures.

RAUDOLF BUCHHEIM founded the first experimental

pharmacology laboratory in his own house in 1849 in germany.

IVAN PAVLOV is one of the most famous scientist used

animals for performing experiments in late 1800’s.

CONT…………

The first animal protection law was proposed in British parliament at 1822, promoted by Charles Darwin, legislation for the protection and regulation of animals.

The bill for protection law of animals has passed in the year 1876.

SIR RAM NATH CHOPRA in INDIA made the beginning in pharmacological research of traditional drugs.

The animal welfare board of INDIA was set up in accordance with section 4 of the prevention of cruelty to animal act 1960.

From the 17 th century there is a oppose to the use of animals in research and the scientific community.

INTRODUCTION

Physiologically and Anatomically there is a similarity between the humans and animals at organs and organ systems, which function in a similar fashion.

This similarity makes animals ideal models for the study and development of products and techniques for humans.

It was the use of animals in the laboratory that lead to the discovery of the diptheria and polio vaccines, insulin for the treatment of diabetes mellitus, heart valve replacement , antibiotic theraphy, manic-depressive drugs and the list goes on and on.

CLASSIFICATIONS OF ANIMAL RESEARCH

Animal research can be divided in to several classifications based on study type.

Experimental designs and procedure are precisely specified and implemented with in each study and the use of any animal must be justified.

Animal research are of following types:Basic research.Applied research.Toxicology testing.Xeno transplantation.

CONT…………

BASIC RESEARCH:

The goal is to investigate how organisms develop,

function & behave.

These studies include embryogenesis and developmental

biology, behavior, evolution and genetics.

Mice and rats account for the vast majority.

CONT…………

APPLIED RESEARCH:

The primary purpose is to solve a specific or practical

problem.

These studies may involve naturally occurring diseases,

induced animal models of human diseases or genetically

modified animals.

Applied often represents the early stage in the drug

discovery process.

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TOXICOLOGY TESTING : This is generally performed by pharmaceutical

companies or contract animal testing facilities to test drugs and other chemicals.

Today all the new drugs must under go rigorous animal testing prior to licensing for human use.

Cosmetic testing fall within this category, and it has become particularly controversial in recent years.

Toxicology testing's are of three types: Acute toxicity testing. Chronic toxicity testing.

TOXICOLOGY TESTING'S

ACUTE TOXICITY : Acute toxicity studies are required

for all drugs. These studies involve single administration

of the agent up to lethal level in at least two species.

CHRONIC TOXICITY : chronic toxicity is a property of a

substance that has toxic effects on a living organism,

when that organism is exposed to the substance

continuously or repeatedly .

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XENO TRANSPLANTATION:

This is the study of transplanting tissues or organs from

one species to another.

It is currently viewed as a mechanism to overcome the

shortage of human organs for organ transplantation.

Recently clinical trials evaluated the transplantation pf

pig insulin secreting cells in to diabetics.

ANIMALS IN USE

Animals used in drug discovery include rats, mice, dogs, cats, primates, rabbits, hamsters, frogs guinea pigs and others. Of which rats, mice, rabbit & guinea pigs are the common animals used in research.

Source for animals in research facilities vary depending upon location, but most are supplied by special dealers.

Regardless of an animals source origin they are protected by laws, regulations and policies to ensure humane treatment.

In united states, under provisions of the animal welfare act (1966), guide lines have been established.

RAT(RATTUS NOVERGICUS)

Strains of rats used in experimental pharmacology are wistar strain, sprauge-dawley and porton.

Rats being small in size (200gm), resemble humans in several organ function and nutrition and sensitive to most of the drugs, make them very use full in experimental pharmacology.

The various tissues used for the study of drugs are colon, stomach uterus, ceacum, vas deference and abdominal smooth musle.

Rat brain tissue is extensively employed in radio-receptor ligand studies.

MICE(MUS MUSCULUS)

Strains of mice used in experimental pharmacology are Swiss strain, Laca andBalb/c.

They are small in size (25-30gms) and extensively used in toxic study, bioassay of drugs(insulin), testing of analgesics, CNS active drugs and chemotherapeutic agents.

Most recently mouse brain tissue as well as primary cell culture of mouse spinal cord neurons are used in neuropharmacology for studying neurotransmitter receptor functions.

RABBITS(LEPUS CURPAEUMS)

Domestic rabbits (2-3kg) are used for pyrogen testing. one of the peculiar thing about rabbits is that they are resistant to the action of atropine as they contain atropinesterase enzyme, the presence of which is genetically determined.

Some of the tissue or organs from rabbits used are heart, aorta, duodenum and ileum.

GUINEA PIG(CAVIA PORCELLUS)

Guinea pigs (400-600gms) are the commonly used experimental animals.

They are used to study local anesthetics, and as a models in experimental amoebiasis and cholera as they are sensitive to these microorganisms.

Guinea pig tissues such as ileum is the most common preparation used to study spasmogen and antispasmodics.

ALTERNATIVES

Most countries adhere to the three R’s : Replacement,

Reduction and Refinement as guiding principles for the

use of animals in research.

The 3 R’s are important from a scientific, ethical and

legal perspective.

In an humane society, there is a clear moral obligation to

minimize the potential pain, suffering or distress of any

animal to an absolute minimum.

REPLACEMENT

Replacement refers to use of non-animal methods over

animal methods when ever it is possible to achive the

same scientific aim.

One aspect of replacement is the use of lower species of

animals whenever possible, using rabbit instead of a dog

or a mouse instead of rabbit

This explains why most research is done on mice and

rats.

REDUCTION

Reduction refers to obtain equivalent level of

information by using fewer animals or increased

information from the same number of animals.

Investigators must ensure that their research design is

robust and they have significant animal numbers to

provide statistically relevant data, while keeping animal

numbers to a minimum.

REFINEMENT

Refinement refers to methods to enhance animal welfare

and minimize distress, suffering and potential pain for

the animals.

The goals of refinement are to improve the quality of life

for the animals and in doing so improve the quality of

science.

ETHICAL REQUIREMENTS

In order to make judicious use of animals for experimental purposes, the scientific societies and institutions have put forth ethical guide lines for investigators.

It is a mandatory to have institutional ethical committees and to have the approval of experimental protocols.

ethical committees also provide guidelines for proper breeding and storage facilities and protection against inhumane treatment.

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