Jawaharlal Nehru Technological University Hyderabad B. Pharmacy IV EXPERIMENTAL PHARMACOLOGY Previous Question Paper (September-2021 - R17)

Laboratory animals are classified based on their biological characteristics, genetic status, and intended research application. The primary classifications include:

• Species and Strain: Commonly used species include rodents (mice, rats, guinea pigs, hamsters), rabbits, and larger animals (dogs, cats, non-human primates). Strains are categorized as inbred (genetically identical) or outbred (genetically diverse).
• Microbiological Status: Animals are classified by their microbial profile, ranging from conventional (housed in standard conditions) to specific pathogen-free (SPF), axenic (germ-free), and gnotobiotic (defined microbial flora).
• Genetic Modification: This category includes wild-type animals and genetically modified organisms, such as transgenic, knockout, and knock-in models.

Transgenic Animals are organisms whose genome has been altered by the stable introduction of foreign DNA (transgene) into their germline. This process allows researchers to study gene function, disease mechanisms, and therapeutic interventions in a living system.

Key aspects of transgenic animals include:

• Methodology: The most common technique involves microinjection of DNA constructs into the pronucleus of a fertilized oocyte, which is then implanted into a pseudopregnant surrogate mother. Alternative methods include viral vector-mediated gene transfer or the use of embryonic stem (ES) cells.
• Applications: These models are essential for studying human genetic diseases, such as cancer, Alzheimer's, and diabetes. They are also used to produce therapeutic proteins (biopharming) and to test the efficacy and safety of new pharmacological agents.
• Advantages: Transgenic models provide a controlled environment to observe the phenotypic expression of specific genes and allow for the creation of humanized models that better mimic human pathophysiology compared to traditional animal models.
• Ethical Considerations: The creation and use of transgenic animals are strictly regulated by institutional animal ethics committees to ensure the welfare of the animals and to minimize suffering, adhering to the 3Rs (Replacement, Reduction, and Refinement).