Necrosis is accompanied by mitochondrial swelling and increased plasma membrane permeability, while apoptosis involves an articulated breakdown of the cell into membrane-bound apoptotic bodies. Lactate dehydrogenase (LDH) is a soluble cytosolic enzyme that is released into the culture medium following loss of membrane integrity resulting from cell- or compound-induced cytotoxicity. LDH activity, therefore, can be used as an indicator of cell membrane integrity and serve as a general means to assess cell viability by measuring plasma membrane permeability. Cayman's LDH Cytotoxicity Assay Kit measures cell death in response to chemical compounds or environmental factors using a coupled two-step reaction. In the first step, LDH catalyzes the reduction of NAD+ to NADH and H+ by oxidation of lactate to pyruvate. In the second step of the reaction, diaphorase uses the newly-formed NADH and H+ to catalyze the reduction of a tetrazolium salt (INT) to highly-colored formazan which absorbs strongly at 490-520 nm.Needed but not supplied: Please download the kit booklet to verify if UltraPure Water (Milli-Q or equivalent) or any other components are needed for this assay.WARNING This product is not for human or veterinary use.
Cell death can occur either by apoptosis, a highly regulated biochemical pathway involving signal transduction cascades, or by necrosis. Necrosis is accompanied by mitochondrial swelling and increased plasma membrane permeability, while apoptosis involves an articulated breakdown of the cell into membrane-bound apoptotic bodies. There are a number of assays that are designed to measure cytotoxicity and cell death, independent of mechanism. Most of these assays assess cell viability by measuring plasma membrane permeability.Lactate dehydrogenase is a stable, soluble enzyme located in the cytosol of many different cell types. The enzyme is released into the surrounding culture medium upon plasma membrane damage. LDH activity in the culture medium can, therefore, be used as a reliable indicator of cell membrane integrity, and thus a measurement of cytotoxicity.
[1] Bonfoco, E. et al. (1995) Proc Natl Acad Sci U S A 92, 7162-6.
[2] Haslam, G. et al. (2000) Cytotechnology 32, 63-75.
