In Vitro
Also known as: in vitro
In vitro refers to research conducted outside a living organism, in a test tube or cell culture environment. Results are useful for identifying mechanisms but may not reflect what occurs in a living system.
Overview
The term 'in vitro' is Latin for 'in glass,' referring to laboratory glassware used in early cell biology. Modern in vitro research uses cell lines, primary cell cultures, and tissue explants to study molecular mechanisms, receptor binding, enzyme activity, and cytotoxicity. In vitro experiments are valuable for establishing whether a compound interacts with its intended target and understanding basic mechanisms. However, cells grown in culture behave differently from cells in intact tissue — they lack normal blood supply, immune interactions, hormonal milieu, and systemic feedback. A compound that kills cancer cells in a dish may have no effect on cancer in a living animal, and a compound harmless to cells in culture may be toxic in a living system.
Related Terms
Frequently asked questions
What types of experiments are done in vitro?+
Cell viability assays, receptor binding studies, gene expression analysis, enzyme activity measurements, and cytotoxicity screening are all commonly conducted in vitro.
Is in vitro evidence sufficient to conclude a peptide is effective?+
No. In vitro findings establish mechanistic plausibility but cannot predict efficacy or safety in living organisms. In vivo (animal) and eventually clinical studies are needed for stronger evidence.
Can in vitro results predict in vivo results?+
Sometimes, but frequently not. The translation from in vitro to in vivo is imperfect because of pharmacokinetics, distribution, metabolism, and complex systemic interactions absent in cell culture.