Biomedical research and model animals

The use of model animals has contributed to numerous scientific discoveries throughout modern human history. Their use in biomedical research and the development of new drugs is facilitated by the similarities in physiology and anatomy between humans and other animals, especially vertebrates and mammals. In vivo experiments are based on the principle of comparative medicine since animals replicate the physiological and pathological processes of humans (Mukherjee et al., 2022).

Among the models most commonly used by researchers worldwide are Caenorhabditis elegans (nematode); Drosophila or fruit fly (insect); Danio rerio or zebrafish (fish); Xenopus (frog); and various mammals such as cats, dogs, pigs, and monkeys, the latter being particularly used due to its proximity and similarity to humans (Hickman et al. 2016).

But is animal experimentation really necessary?

Scientific research is strongly directed towards the development of new techniques and technologies that allow the avoidance of animal use; however, in the biomedical field, its use remains essential. Consider the effects of a therapy that affects the entire organism and has repercussions on different organs; these effects would be impossible to evaluate by testing specific cells or through bioinformatic simulations alone. This is why the development of drugs and vaccines considers animal experimentation a crucial step before proceeding to clinical trials on humans. In any case, animal welfare is always a top priority, and research follows the fundamental principle of protecting laboratory animals according to the so-called “3R principle” (MacArthur Clark, 2018):

• REPLACEMENT, which means keeping in mind the ultimate goal of replacing animals with alternative methods.
• REDUCTION, that is, minimizing the number of animals required.
• REFINEMENT, which involves improving experimental conditions to reduce animal suffering.

It is important to remember that in Italy, the use of animals for scientific purposes is regulated by Legislative Decree No. 26 of March 4, 2014. European regulations also stipulate that to protect the welfare of animals, an Animal Welfare Body must be appointed for every institution operating in this sector. This body is made up of a Welfare and Care Officer, a veterinarian, and a scientific member. The role of the Animal Welfare Body is to examine research projects to ensure compliance with national, European, and international regulations, evaluate the harm/benefit ratio, establish possible replacement with alternative methods, and finally submit projects to the Ministry of Health for approval if all necessary requirements are met.