Ex vivo

Ex vivobrainstem: (A)coronalview displaying the anterior portion of the tissue sample, (B)sagittalview displaying the left-hand side of the tissue sample

Ex vivo(Latin:"out of the living" ) literally means that which takes place outside anorganism.In science,ex vivorefers toexperimentationor measurements done in or ontissuefrom an organism in an external environment with minimal alteration of natural conditions.

A primary advantage of usingex vivotissues is the ability to perform tests or measurements that would otherwise not be possible orethicalin living subjects. Tissues may be removed in many ways, including in part, as wholeorgans,or as larger organ systems.

Examples ofex vivospecimen use include:

• Acute brain slice methodSlice preparation;
• bioassays;
• usingcancerouscell lines, likeDU145for prostate cancer, indrug testingofanticancer agents;
• measurements ofphysical,thermal,electrical,mechanical,opticaland other tissue properties, especially in variousenvironmentsthat may not be life-sustaining (for example, at extremepressuresortemperatures);
• realistic models forsurgical proceduredevelopment;
• investigations into the interaction of different energy types with tissues; or
• as phantoms inimagingtechnique development.

Demonstration of isolation of choroid from the mouse eye

The termex vivomeans that the samples to be tested have been extracted from the organism. The termin vitro(lit. "within the glass" ) means the samples to be tested are obtained from a repository. In the case of cancer cells, a strain that would produce favorable results, then grown to produce a control sample and the number of samples required for the number of tests. These two terms are not synonymous even though the testing in both cases is "within the glass".

Incell biology,ex vivoprocedures often involve living cells or tissues taken from an organism and cultured in alaboratoryapparatus, usually under sterile conditions with no alterations, for up to 24 hours to obtain sufficient cells for the experiments. Experiments generally start after 24 hours of incubation. Using living cells or tissue from the same organism are still considered to beex vivo.One widely performedex vivostudy is the chickchorioallantoic membrane(CAM) assay. In this assay,angiogenesisis promoted on the CAM membrane of achickenembryooutside the organism (chicken).

In situlung function evaluation, and assessment oftotal lung capacity(TLC) and basalelastanceafter performing a recruitment maneuver

See also

• Animal testing
• In silico
• In situ
• In utero
• In vitro
• In vivo