Revision 5

#37291Store at -20C

Cell Signaling Technology

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For Research Use Only. Not for Use in Diagnostic Procedures.
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Product Information

Storage

All components in this kit are stable for at least 12 months when stored at the recommended temperature.

Product Description

The LDH Cytotoxicity Assay Kit can be used for quantitatively measuring cytotoxicity in response to chemical compounds as well as assaying cell-mediated cytotoxicity using a coupled two-step, colorimetric reaction. In the first step, lactate dehydrogenase (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. The amount of formazan produced is proportional to the amount of LDH released into the culture medium as a result of cytotoxicity.

In a prototypical cytotoxicity assay, target cells are cultured with a cytotoxic chemical agent or a cytotoxic cell (e.g., NK cells) to induce target cell death and LDH release. The LDH-containing supernatants are transferred to wells of a new assay plate and mixed with the LDH Reaction Solution. After an incubation of 30 minutes at room temperature, the absorbance at 490 nm (A490) is read using a plate reader. Cells treated with cytotoxic agents or cytotoxic cells will release an amount of LDH that falls between the maximum release control level and the spontaneous release control level.

Background

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 (1). 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 (2).

Lactate dehydrogenase (LDH) 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.

Species Reactivity

Species reactivity is determined by testing in at least one approved application (e.g., western blot).

Cross-Reactivity Key

H: human M: mouse R: rat Hm: hamster Mk: monkey Vir: virus Mi: mink C: chicken Dm: D. melanogaster X: Xenopus Z: zebrafish B: bovine Dg: dog Pg: pig Sc: S. cerevisiae Ce: C. elegans Hr: horse GP: Guinea Pig Rab: rabbit All: all species expected

Trademarks and Patents

Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.
All other trademarks are the property of their respective owners. Visit cellsignal.com/trademarks for more information.

Limited Uses

Except as otherwise expressly agreed in a writing signed by a legally authorized representative of CST, the following terms apply to Products provided by CST, its affiliates or its distributors. Any Customer's terms and conditions that are in addition to, or different from, those contained herein, unless separately accepted in writing by a legally authorized representative of CST, are rejected and are of no force or effect.

Products are labeled with For Research Use Only or a similar labeling statement and have not been approved, cleared, or licensed by the FDA or other regulatory foreign or domestic entity, for any purpose. Customer shall not use any Product for any diagnostic or therapeutic purpose, or otherwise in any manner that conflicts with its labeling statement. Products sold or licensed by CST are provided for Customer as the end-user and solely for research and development uses. Any use of Product for diagnostic, prophylactic or therapeutic purposes, or any purchase of Product for resale (alone or as a component) or other commercial purpose, requires a separate license from CST. Customer shall (a) not sell, license, loan, donate or otherwise transfer or make available any Product to any third party, whether alone or in combination with other materials, or use the Products to manufacture any commercial products, (b) not copy, modify, reverse engineer, decompile, disassemble or otherwise attempt to discover the underlying structure or technology of the Products, or use the Products for the purpose of developing any products or services that would compete with CST products or services, (c) not alter or remove from the Products any trademarks, trade names, logos, patent or copyright notices or markings, (d) use the Products solely in accordance with CST Product Terms of Sale and any applicable documentation, and (e) comply with any license, terms of service or similar agreement with respect to any third party products or services used by Customer in connection with the Products.

Revision 5
#37291

LDH Cytotoxicity Assay Kit

LDH Cytotoxicity Assay Kit: Image 1 Expand Image
Determination of Optimum Cell Number for LDH Cytotoxicity Assay: HeLa cells were seeded into a 96-well plate at varying densities using media containing 10% FBS. After overnight incubation, the cells were replaced with serum-free media and then treated with either Assay Buffer (Spontaneous LDH Release) or 10% Triton X-100 solution (Maximum LDH Release). After treatment, the medium was removed and placed into a new 96-well plate. The amount of LDH released into the medium was determined using the LDH Cytotoxicity Assay Kit protocol.
LDH Cytotoxicity Assay Kit: Image 2 Expand Image
Determination of Staurosporine-induced LDH Release: HeLa cells were seeded in medium supplemented with 1% FBS at density of 10,000 cells/well and then treated for 24 hr with either vehicle control or 1 μM Staurosporine #9953. LDH released into the medium and percent cytotoxicity was calculated using the LDH Cytotoxicity Assay Kit protocol.