Why are drugs tested on mice? - briefly
Mice provide a biologically relevant model with genetic and metabolic pathways comparable to humans, enabling evaluation of a compound’s safety and efficacy before human trials. Their rapid breeding, low maintenance cost, and well‑characterized genome make them essential for preclinical research.
Why are drugs tested on mice? - in detail
Drug development relies on animal models because they provide a living system in which to assess pharmacological activity, toxicity, and pharmacokinetics before human exposure. Mice are preferred for several practical and scientific reasons.
First, their genome shares approximately 85 % of protein‑coding genes with humans, allowing extrapolation of molecular mechanisms. Genetically engineered strains—knockouts, transgenics, and humanized models—enable precise investigation of target pathways and disease phenotypes.
Second, mice reproduce quickly and have a short lifespan, which compresses study timelines. A single breeding cycle can be completed in 6–8 weeks, permitting rapid generation of sufficient sample sizes for statistical analysis.
Third, maintenance costs are low relative to larger species. Standard laboratory facilities can house large cohorts, ensuring reproducibility across experiments and compliance with regulatory guidelines that mandate pre‑clinical safety data from at least one rodent species.
Fourth, physiological parameters such as metabolism, immune response, and organ architecture are sufficiently comparable to humans to reveal adverse effects that may not appear in in‑vitro systems. Dose‑response curves, bioavailability, and tissue distribution can be measured accurately in vivo.
Finally, regulatory agencies (e.g., FDA, EMA) require documented animal testing as part of the Investigational New Drug (IND) application. Compliance with these mandates ensures that candidate compounds meet safety thresholds before entering clinical trials.
Limitations include interspecies differences that can lead to false positives or negatives, and ethical considerations that drive the development of alternative methods such as organ‑on‑a‑chip platforms and computational modeling. Nonetheless, mice remain a cornerstone of pre‑clinical research because they balance genetic relevance, experimental efficiency, and regulatory acceptance.