Lactate dehydrogenase leakage

Assays are frequently needed to detect marked and acute cytotoxicity that may confound the interpretation of cell-based efficacy assays. Neutral red uptake is one of the most commonly used cytotoxicity assays and is used in the regulatory phototoxicity assay on NT3 fibroblasts [13]. It has been show to be more sensitive than assays for mitochondrial reductive capacity such as the tetrazolium reductase assays, ATP depletion assays, or for cell permeabilization or mpture such as dye uptake or lactate dehydrogenase leakage. Lysosomes take up, protonate and trap neutral red when cellular ATP production is sufficient to maintain pH gradients. 

Timbrell et al. (1996) reported that much higher hydrazine concentrations were required in rat hepatocyte cultures in comparison to plasma concentrations in male Sprague-Dawley rats to elicit the following hepatic/hepatocellular effects lactate dehydrogenase leakage, ATP and GST depletion, increase in citrulline level, protein synthesis inhibition, taurine leakage and triglyceride accumulation. 

Studies of ibuprofen and other NSAIDs have produced toxic effects at concentrations 10 times therapeutic in cultured hepatocytes. No adverse effect on cell survival was noted at therapeutic concentrations of ibuprofen in this model, although increases in lactate dehydrogenase leakage were prominent. 

In rat hepatocytes, the compound curcumin was cyto-protective at concentrations of 0.05 mM, whereas at 5 mM the observed protective effect on lipid peroxidation was accompanied with a tendency to increase cellular glutathione depletion and lactate dehydrogenase leakage (Donatus et al. 1990). 

Cytotoxicity is the most important parameter to evaluate the biocompatibility of biodegradable polymers in vitro. Various assays are available to measure cell viability after exposure to polymer extracts, such as lactate dehydrogenase leakage assay (LDH), neutral red uptake assay (NRU), and trypan blue assay. Table 20.5 summarizes the different types... 

Leakage of cell contents (e.g., lactate dehydrogenase) and entry of extracellular dyes (e.g., Trypan blue, DNA stains such as TOTO-3)... 

Dibromo- and 1,1-dichloro-l-phenylbenzostiboles markedly increased the lactate dehydrogenase (LDH) activity leaked into the medium from vascular endothelial cells after 24 h treatment, suggesting that these four compounds have strong cytotoxicity to vascular endothelial cells, caused leakage in vascular smooth muscle cells, and destroyed the monolayer of both endothelial and smooth muscle cell layers <2005JHS333>. 

Hannemann Jand Baumann K. Inhibition of lactate-dehydrogenase by cisplatin and other platinum-compounds enzyme leakage of LDH is not a suitable method to measure platinum-compound-induced kidney cell damage nv/fro. ResCommun Chem Pathol Pharmacol 60 371 -379,1988. 

The cell membrane serves as a protective barrier in renal cells. It is the initial site which p-lactams encounter in their journey to the cellular environment from the blood or tubular fluid, p-lactams may disrupt the functional organization of the membrane through peroxidation of membrane lipids, which, in turn, leads to the inability of membrane to serve as an osmotic barrier and causes the cytosol contents to leak. As a result of the cephalosporins disruptive effect on cell membrane, increased leakage of the cytosolic enzyme lactate dehydrogenase (LDH) occurs. The increased LDH concentration was from the cytosol of the renal cortex [49,71] or from isolated proximal and distal tubular cells [39] or in the urine of experimental animals [39]. The results of these studies indicate that plasma membrane became permeable to large molecules such as LDH. After cephalosporin treatment, cephaloridine caused the greatest decrease of LDH concentration in cytosol [49]. Whereas, cephaloridine induced a greater release of LDH from proximal tubular cells than cepha-lothin and cephalexin, distal cells were not affected by any of these cephalosporins [38,39]. 

According to the results of lactate dehydrogenase (LDH) leakage and microscopic examination, 0.5 or 1 mM DAS treatment did not have any adverse effects on the viability of hepatocytes. Intracellular GSH contents of cells treated with 0.5 and 1 mM DAS (58.6 and 66.4 nmol GSH/mg protein, respectively) were higher than in the controls (54.2 nmol GSH/mg protein), around 8-23%, at 24 hr of incubation a significant difference (P < 0.05) was observed for 1 mM DAS treatment at 48 hr. This phenomenon... 

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