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Repertoire of In vitro cell based models at DRF as alternatives to animal testing

“Life is life–whether in a cat, or dog or man. There is no difference there between a cat or a man. The idea of difference is a human conception for man’s own advantage.” Sri Aurobindo

As a cell biologist, I have realized that cells are relevant and beautiful test systems to understand the functioning and mechanism of any agent, drug, new molecule, herbal agent etc. What we are able to elucidate at cellular level is what we expect to be translated into an animal model and work as a proof of concept. This forms the foundation of preclinical research – translation of in vitro observations into in vivo data and validates the sequence of transition of a hypothesis into results. This principle emphasizes the importance and role of animal testing in drug discovery and development. Because of their physiological similarity to human beings, animals have been extensively used in past in drug research as important experimental subjects.

Animal models have been widely employed to assess pharmacological activity and safety of new agents. To predict toxicity, corrosivity, and other safety variables in addition to effectiveness of a new product for humans, traditional testing of new drugs involves the use of animals on a large scale. As the records say, each year, more than 110 million animals—including mice, rats, frogs, dogs, cats, rabbits, hamsters, guinea pigs, monkeys, fish, and birds—are killed in U.S. laboratories for biology lessons, medical training, curiosity-driven experimentation, and chemical, drug, food, and cosmetics testing [1]. The experimental procedures on these animals are torturous for the animals, for e.g. before their deaths, some are forced to inhale toxic fumes, others are immobilized in restraint devices for hours, some have holes drilled into their skulls, and others have their skin burned off or their spinal cords crushed [1].

While researchers and activists have realized the cruelty on animals, various animal testing bans are now being implemented. Many countries have either completely banned or limit and regulate the usage of animals for research in various countries [2]. Registration, Evaluation and Authorization of Chemicals (REACH; regulation 1907/2006) is in effect in the European Union (EU) and safety information must be provided on all chemicals that are either sold, manufactured or imported into the EU. Animal testing ban was made effective on chemicals to be used in cosmetics in EU from March 2009.

Realizing the importance in drug discovery, many alternative methods for animal testing are being developed by researchers all over the world, which have been shown to lead to safer and more effective products for humans. Alternative testing methods offer many advantages over traditional animal tests-including being more humane, reliable, accurate, more cost-effective, fast, practical, and expedient. Alternatives to animal testing implies to the development and implementation of test methods that avoid or minimize the use of live animals.

Alternate testing of cosmetics follows the 4R principle- Reduce, Refine, Replace and Rehabilitation of the use of animals in research. At Dabur Research Foundation, We have developed a huge spectrum of in vitro/ex vivo cell-based models in varied therapeutic applications such as cancer, hematotoxicity, immunomodulation, inflammation, dermatology, neurological health and skin-care. These models profoundly increase the understanding of biological activities of test compounds and may serve as in vitro alternatives to similar tests conducted in animals. Relevant cell types with appropriate stimulus/damage and most suitable end points are appropriately utilized. The models available might play a vital role in strengthening the concept of animal free/minimizing testing as they mimic the cellular environment of humans. In addition to the efficacy assays, DRF also has the capability to offer in-vitro safety assays for Cosmetics. In-vitro safety assays are performed as per the regulatory guidelines such as OECD and INVITTOX guidelines. Various assays performed at DRF as an alternate to testing on animals include:

  • In vitro 3D-Skin Corrosion: Skin corrosion refers to the production of irreversible damage to the skin manifested as visible necrosis through the epidermis and into the dermis, following the application of a test chemical. Assay involves the use of in-vitro 3D-Skin.
  • In vitro 3D-Skin Irritation: Skin irritation refers to the production of reversible damage to the skin occurring after exposure to a substance or mixture.
  • HET-CAM (Hen’s Egg Test-Chorioallantoic Membrane) assay: This assay evaluates the potential ocular irritancy of a test substance as measured by its ability to induce toxicity in the chorioallantoic membrane of a chicken. Effects are measured by the onset of (1) haemorrhage; (2) coagulation; and (3) vessel lysis. These assessments are considered individually and then combined to derive a score, which is used to classify the irritancy level of the test substance.

We had showcased our battery of standardized and validated in vitro models for evaluating the efficacy and safety of agents at various national and international forums [3-4]. These cell-based assays not only potentially accelerate the research of new therapeutic agents but may also serve as alternatives to equivalent animal tests in vivo by reducing the number of animals and severity of procedures. These in vitro assay systems contribute towards understanding of complex biological action of new compounds at cellular level. Shortlisting of hit/active compounds by in-vitro screening obviates the need of large number of testing animals while meeting 3R’s principle of “Reduce, Refine and Replace”.

References

  1. https://www.peta.org/issues/animals-used-for-experimentation/animals-used-experimentation-factsheets/animal-experiments-overview/
  2. Ban of Cosmetic Testing on Animals: A Brief Overview, Sreedhar D et al. Int J Cur Res Rev | Vol 12 • Issue 14 • July 2020.
  3. “IN VITRO SCREENING TOOLS TO ACCELERATE NEW DRUG DISCOVERY: ALTERNATIVES TO ANIMAL TESTING” at Ramanbhai Foundation 6th International Symposium “Advances in New Drug Discovery Technologies And Translational Research held at Zydus Research Centre at Ahmedabad, India, 4th-6th Feb 2013.  https://www.researchgate.net/publication/325896719_IN_VITRO_SCREENING_TOOLS_TO_ACCELERATE_NEW_DRUG_DISCOVERY_ALTERNATIVES_TO_ANIMAL_TESTING
  4. “Use of animals and alternatives in biomedical research with special reference to drug discovery and drug development” organized by AMITY institute of pharmacy in association with CPCSEA, India, 14th – 15th Feb 2013.