• Biomedical Science Letters
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• v.27 no.3
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• pp.170-176
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• 2021

Thapsigargin (TG), a sarco/endoplasmic reticulum (ER) Ca²⁺-ATPase (SERCA) inhibitor, has been widely used as an agonist for platelet aggregation for decades. In this study, we investigated the effect of TG on the release of lactate dehydrogenase (LDH) for platelets and elucidated its mechanism. Platelet LDH release and platelet aggregation were increased by TG treatment; 1,000 nM of TG induced the complete lysis of platelets. Other agonists such as collagen (2.5 ㎍/mL), thrombin (0.1 U/mL), and ADP (10 mM) did not induce significant platelet LDH release despite platelet aggregation. Finally, we investigated the effects of pharmacological inhibitors on TG-induced platelet aggregation and LDH release. SP600125, a JNK inhibitor, and LY294002, a PI-3K inhibitor, inhibited TG-induced platelet LDH release but not platelet aggregation. Forskolin, an adenylyl cyclase activator, also inhibited LDH release without affecting platelet aggregation by TG. These results suggest that the TG-induced platelet aggregation was accompanied by LDH release but regulated by a different signaling pathway.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.115-121
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• 2000

To evaluate the cytotoxicity of cadmium compounds, this study was conducted to measure the in vitro magnetometry, LDH release and cellular apoptosis using alveolar macrophages of hamsters. A series of magnetometric measurements in cadmium-added groups showed a significant dose-dependent decay of the relaxation curves. The LDH release rates showed a dose-dependently increasing tendency as the dose gradually increased. The positive rates of apoptosis were significantly higher in cadmium-added groups than the control groups. Conclusively, the cytotoxicity increased in a dose dependent way as the concentration of cadmium added increased, which reflected in the decay of relaxation curve in magnetometry, and increased LDH release rate and positive rate of apoptosis.

• Korean Journal of Pharmacognosy
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• v.25 no.4 s.99
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• pp.388-394
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• 1994

80% Methanol extracts of 44 traditional drugs used for the treatment of liver diseases or tonic effects were screened for anti-hepatotoxic activity by in vitro assay using $CCl_4-induced$ cytotoxicity in primary cultured rat hepatocytes. $CCl_4-induced$ cytotoxicity was evaluated by determination of LDH, GOT or GPT activity in the medium. Rehmaniae Radix Preparata and Gelantina nigra inhibited the release of LDH, GOT or GPT from $CCl_4-treated$ hepatocytes. Gibotii Rhizoma and Eucommiae Cortex showed inhibitory effect on release of LDH from normal hepatocytes as well as $CCl_4-treated$ hepatocytes. Eucommiae Cortex and Lili Bulbus decreased release of GOT and LDH from normal hepatocytes, respectively. Astragali Radix inhibited release of GPT in $CCl_4-treated$ hepatocytes. Phlomidis Radix, Imperatae Rhizoma, Cistanchis Herba, Broussonetiae Fructus, Asparagi Tuber, Trigonellae Semen and Polgonati Rhizoma inhibited release of LDH from $CCl_4-treated$ hepatocytes. Among 44 traditional drugs, most of them released LDH, GOT or GPT at the dose of 1 mg/ml in normal hepatocytes, and Drynariae Rhizoma, Acanthopanacis Cortex, Longanae Arillus, Atratylodis Rhizoma and Ecliptae Herba increased $CCl_4-induced$ cytotoxicity.

• Biomedical Science Letters
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• v.7 no.3
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• pp.127-131
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• 2001

This study was undertaken to examine the effect of amino acids on anoxia-induced cell injury in rabbit renal cortical slices. In order to induce anoxic cell injury, slices were exposed to a 100% $N_2$ atmosphere and control slices were exposed to 100% $O^2$. Irreversible cell injury was estimated by measuring lactate dehydrogenase (LDH) release and alterations in renal cell function were examined by measuring p-aminohippurate (PAH) uptake. Anoxia caused the increase in LDH release in a time-dependent manner. Glycine and glutathione almost completely prevented anoxia-induced LDH release. Of amino acids tested, glycine and alanine exerted the protective effect against anoxia-induced cell injury. However, asparagine with amide side chain, leucine and valine with hydrocarbon side chain, and basic amino acids (lysine, histidine, and arginine) were not effective. Anoxia-induced inhibition of PAM uptake was prevented by glycine. ATP content was decreased by anoxia, which was not affected by glycine. Anoxia-induced depletion of glutathione was significantly prevented by glycine. These results suggest that neutral amino acids with simple structure exert the Protective effect against anoxia-induced cell injury the involvement of specific interaction of amino acids and cell structure.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.122-126
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• 2004

Biofunctional nanohybrids are synthesized from layered double hydroxide (LDH) and the vitamins such as ascorbic acid and topopherol acid succinate. Either ion exchange or copricipitaion leads to successful intercalation of the vitamins into gallery space of LDH that offers a new route to safe preservation of bioactivity as well as controlled release. Intercalations of vitamins are clearly reflected on the increase in the basal spacing of ZnAl-(Nitrate) LDH from 8.5 ${\AA}$ to 10.5 ${AA}$ for ascorbate, and 49.0 ${AA}$ for tocopherol acid succinate, respectively. No significant change in UV-Vis and IR absorption characteristics of the intercalated vitamins strongly supports the safe maintenance of their bioactivities without any deterioration of chemical and structural integrity. Furthermore, it is shown that the hybridized vitamins could be discharged in a controlled kinetics.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.93-100
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• 1999

The present study was designed to assess the roles of $PLA_2$ activation and arachidonic acid (AA) metabolites in hypoxia-induced renal cell injury. Hypoxia increased LDH release in a dose-dependent manner in rabbit renal cortical slices, and this increase was significant after 20-min hypoxia. The hypoxia-induced LDH release was prevented by amino acids, glycine and alanine, and extracellular acidosis (pH 6.0). Buffering intracellular $Ca^{2+}$ by a chelator, but not omission of $Ca^{2+}$ in the medium produced a significant reduction in hypoxia-induced LDH release. The effect of hypoxia was blocked by $PLA_2$ inhibitors, mepacrine, butacaine, and dibucaine. A similar effect was observed by a 85-kD $cPLA_2$ inhibitor $AACOCF_3.$ AA increased hypoxia-induced LDH release, and albumin, a fatty acid absorbent, prevented the LDH release, suggesting that free fatty acids are involved in hypoxia-induced cell injury. These results suggest that $PLA_2$ activation and its metabolic products play important roles in pathogenesis of hypoxia-induced cell injury in rabbit renal cortical slices.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.3
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• pp.223-230
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• 2001

Melatonin, a pineal gland hormone, is believed to act as an antioxidant via the stimulation of radical detoxifying enzymes and scavenging of free radicals. In this study, effects of in vitro and in vivo treatments of melatonin on the cisplatin-induced lipid peroxidation, LDH release and plasma creatinine were determined in rabbit renal cortical cells. The level of malondialdehyde (MDA) was assayed as an index of lipid peroxidation and the level of LDH release as an indicator of cellular damage. In in vitro studies, cisplatin increased the levels of MDA and LDH release in a concentration-and time-dependent manner. Melatonin inhibited the cisplatin-induced lipid peroxidation and LDH release in a concentration-dependent manner. The minimal effective concentration of melatonin that significantly reduced the $300\;{\mu}M$ cisplatin-induced lipid peroxidation and LDH release was 1 mM. In in vivo studies, the levels of lipid peroxidation and LDH release in renal cortical cells increased significantly 24 or 48 hours after a single injection of cisplatin (6 mg/kg). When the cisplatin-injected rabbits were pretreated with 10 mg/kg of melatonin, a significant reduction in both lipid peroxidation and LDH release was observed. The plasma creatinine level increased from $0.87{\pm}0.07$ mg/dl in control to $6.33{\pm}0.54$ mg/dl in cisplatin-injected rabbits (P＜0.05). Melatonin partially prevented the increase in serum creatinine level $(1.98{\pm}0.11\;mg/dl)$ by cisplatin (P＜0.05). In the proximal tubules from cisplatin-treated group, tubular cells had microvilli of variable heights. Necrotic debris was seen in tubular lumens. In most of cells, the mitochondria and lysosomes were increased in frequency. The endocytic vacuoles were not prominent and distribution of the brush border was irregular and shortened. These cisplatin-induced morphological changes were moderate in the melatonin-pretreated group. These results suggest that the toxicity of cisplatin is associated with the generation of reactive oxygen free radicals and that melatonin is a powerful antioxidant, which prevents some of the adverse effects of cisplatin.

• Parasites, Hosts and Diseases
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• v.38 no.2
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• pp.99-102
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• 2000

In order to observe the cytotoxicity of Acanthamoeba spp., which were isolated from contact lens containers as ethiological agents for the probable amoebic keratitis in Korea, the crystal violet staining method and LDH release assay were carried out. In the crystal violet staining method, among eight contact lens container isolates, isolate 3 (Acanthauloeba KA/LS5) showed 83.6% and 81.8% of cytotoxicity, and isolate 7 (Acanthamoeba KA/LS37) showed 28.2% and 25.1% of cytotoxicity, in 1 mg/ml and 0.5 mg/ml Iysate treatments, respectively. Acanthamoeba cutbertsoni and A. healyi showed 84.0% and 82.8% of cytotoxicity. Similar results were observed in A. costellunii and A. hafchefti which showed 83.6% and 75.5% or cytotoxicity. Acanthamoeba roureba and A. polyphaga showed 9.0% and 1.7% of cytotoxicity. In the LDH release assay, isolate 3 (20.4%) showed higher cytotoxicity than other isolates in 1 mg/ml Iysate treatment. The results provide that at least isolate 3 has the cytotoxic effect against CHO cells and seems to be the pathogenic strain.

• Biomedical Science Letters
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• v.10 no.4
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• pp.341-346
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• 2004

Tumor necrosis factor-α (TNF-α) or its mRNA expression are increased in acute nephrosis of various types including ischemia/reperfusion injury. This study was undertaken to determine whether pentoxifylline (PTX), an inhibitor of TNF-α production, provides a protective effect against hypoxia-induced cell injury in rabbit renal cortical slices. To induce hypoxia-induced cell injury, renal cortical slices were exposed to 100% N₂ atmosphere. Control slices were exposed to 100% O₂ atmosphere. The cell injury was estimated by measuring lactate dehydrogenase (LDH) release and p-aminohippurate (PAH) uptake. Exposure of slices to hypoxia increased the LDH release in a time-dependent manner. However, when slices were exposed to hypoxia in the presence of PTX, the LDH release was decreased. The protective effect of PTX was dose-dependent over the concentrations of 0.05∼1 mM. Hypoxia did not increase lipid peroxidation, whereas an organic hydroperoxide t-butylhydroperoxide (tBHP) resulted in a significant increase in lipid peroxidation. PTX did not affect tBHP-induced lipid peroxidation. Hypoxia decreased PAH uptake, which was significantly attenuated by PTX and glycine. tBHP-induced inhibition of PAH uptake was not altered by PTX, although it was prevented by antioxidant deferoxarnine. The PAH uptake by slices in rabbits with ischemic acute renal failure was prevented by PTX pretreatment. These results suggest that PTX may exert a protective effect against hypoxia-induced cell injury and its effect may due to inhibition of the TNF-α production, but not by its antioxidant action.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.350-355
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• 2004

Sulforhodamine B (SRB) assay is a rapid, sensitive, and inexpensive method for measuring cell proliferation and chemosensitivity. However, the lactate dehydrogenase (LDH) release assay is generally used to measure cytototoxicity of infectious microorganisms against host cells. In this study, we investigated the possibility of applying the SRB assay to determine cytotoxicity for infectious microorganisms, and compared the results with those obtained by the LDH release assay. We used Vibrio vulnificus as a model of infectious microorganisms. The SRB assay showed that V vulnificus strongly induced cytotoxic activity against human intestinal cells, Caco-2 and INT-407 cells. The degree of cytotoxicity closely correlated with infection time and number ratios of V. vulnificus to intestinal cells (MOI, multiplicity of infection). Furthermore, cytotoxicity values obtained by SRB assay correlated well with results obtained by the LDH release assay, and both assays gave a linear response with respect to MOI Heat-inactivation of V. vulnificus for 35 min at $60^{\circ}C$ did not induce cytotoxic activity, indicating that viability of V. vulnificus is crucial for cytotoxic activity against intestinal cells. Although both assays are suitable as cytotoxicity endpoints, the SRB assay is recommended for measuring cytotoxicity of infectious microorganisms against host cells because of its significantly lower cost and more stable endpoint than the LDH release assay.