Increased expression of heat shock protein (HSP)72 in a human proximal tubular cell line (HK-2) with gentamicin-induced injury.

Gentamicin (GM) has been widely used as an antibiotic and its nephrotoxicity has been recognized. However, the alternation of heat shock protein (HSP) 72 as an inductive protein in proximal tubular cells treated with GM is still unclear. In this study, GM cytotoxicity and its effect on the expression of HSP72 in human kidney proximal tubular (HK-2) cells were measured. HK-2 cells were incubated for 24 hr, 48 hr, 72 hr, and 96 hr with GM only and GM plus MnCl2, respectively. Cytotoxicity was determined by the release of lactate dehydrogenase (LDH). Activity of N-acetyl-beta-D-glucosaminidase (NAG) and effects of GM on oxidation in HK-2 cells were investigated by measurements of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity, and the ability of viable cells to reduce a tetrazolium-based compound (MTT). The expression of HSP72 was measured by immunocytochemistry, Western blotting and RT-PCR. Cells were exposed to GM at a concentration of 100 microg/ml. After 24 hr MTT uptake decreased significantly and then gradually until 96 hr. LDH release increased time-dependently from 24 hr to 72 hr, but decreased at 96 hr compared with the data at 72 hr when cells were treated with GM only. Both results of NAG and SOD activities and results of MDA content were similar to that of the LDH release. The amount of HSP72 positive cells increased at 24 hr after exposure to GM up to 72 hr. HSP72 expression increased significantly from 24 hr, and reached its peak at 72 hr when cells were treated with GM only. Furthermore, the change of the HSP72 gene transcription was similar to the expression of HSP72. These results demonstrated that GM treatment could induce damage to HK-2 cells and that the expression of HSP72 increased when cells were injured by GM.

Increased Expression of Heat Shock Protein 72 Protects Renal Proximal Tubular Cells from Gentamicin-induced Injury

The nephrotoxicity of gentamicin (GM) has been widely recognized. Heat shock protein 72 (HSP72) has been reported to be a cytoprotectant. However, its cytoprotective effect against GM induced kidney injury has not yet been studied. In this study, we investigated the cytoprotective effect of HSP72 on GM-induced nephrotoxicity in vitro. Human Kidney tubular cell line, HK-2 cells were divided into four groups: control group, GM group (cells incubated with GM only), heat shock (HS) group (cells incubated at 43 degrees C for 30 min), and GM plus HS group, respectively. Lactate dehydrogenanse (LDH) release increased time-dependently from 24 hr to 96 hr compared to the data of cells treated with GM only. Results of NAG activities, superoxide dismutase (SOD) activities and malondialdehyde (MDA) content were similar to that of the LDH release. The amount of HSP72 positive cells increased significartly at 72 hr after cells were treated with GM only. Both HSP72 protein and gene expression increased significantly at 72 hr when cells were treated with GM. On the other hand, HS induced HSP72 expression markedly. Pretreatment of HS inhibited HK-2 cells from GM-induced injury. It could reduce LDH release and NAG activity. HS also increased SOD activity, and decreased MDA content when cells were damaged by GM. These findings suggested that HS may protect kidney cells from GM-induced injury. Pre-induction of HSP72 may provide therapeutic strategies for nephrotoxicity induced by GM.

Effect of dexamethasone Angelica sinensis polysaccharide prodrug on trinitrobenzene sulfonic acid induced ulcerative colitis in rats / 中国临床药理学与治疗学

AIM:To explore the therapeutic effect of dexamethasone Angelica sinensis polysaccharide prodrug(DEX-AP) on trinitrobenzene sulfonic acid(TNBS) induced ulcerative colitis(UC) in rats and its side effects.METHODS: The experimental UC rats were induced by clusis of the solution of TNBS in 45% alcoho1(50(mg?ml~(-1))).The UC rats were orally administrated with(0.25)(?mol?kg~(-1)?d~(-1)) DEX and(0.05),(0.25),(1.25)(?mol?kg~(-1)?d~(-1)) DEX-AP(calculated by carried DEX in DEX-AP) for 7 days,respectively.The rats were killed after the amount of peripheral blood lymphocyte was counted,then the spleen,thymus and colon were separated and weighted.After the ulcerative area of colon was calculated,the colonic myeloperoxidase(MPO) activity was determined and parts of colon were paraffin sectioned and examined under light microscope by HE stain.RESULTS: After the UC rats were administrated with different doses of DEX-AP for 7 days,the ulcerative area,the weight and the MPO activity of colon reduced significantly.The reduction of MPO activity was correlated to the dose of DEX-AP and the MPO activity with DEX-AP at the doses of(0.25),(1.25)(?mol?kg~(-1)?d~(-1)) reduced more significantly than that with DEX at the the dose of(0.25)(?mol?kg~(-1)?d~(-1)).The number of peripheral blood lymphocyte,spleen weight and thymus weight of UC rats reduced significantly at the dose of(0.25)(?mol?kg~(-1)?d~(-1)) DEX(P

Gender-based differences in genistein metabolism in rat liver microsomes / 中国药理学通报

Aim To study the gender-based difference in genistein metabolism in rat liver microsomes in vitro.Methods Liver microsomes was obtained from male and female rats.The optimized system of enzyme catalytic reaction of genistein in rat liver microsomes was set up.The reaction velocity of genistein in female and male rat liver microsomes was assessed by incubating genistein with CYP1A2 antibody or specific CYP1A2 inhibitor furafylline,and the percentage of the relative metabolism of genistein of CYP1A2 was derivated by using the data of the reaction velocity.Results The metabolism of genistein by microsomes was inhibited by CYP1A2 antibody(1 ∶400)after incubation for 30 min.The percentage of the control metabolism of genistein of microsomes in male and female rat were 20.95%?2.13% and 13.73%?1.26%respectively(P

Colon-targeted delivery system of dexamethasone-angelica sinensis polysaccharides prodrug in rats / 中国临床药理学与治疗学

AIM: To explore the transport and delivery of active drug from dexamethasone-angelica sinensis polysaccharides prodrug in the gastrointestinal tract of rats. METHODS: Dexamethasone and the prodrug were orally administered to rats at the dose of 1.96 mg?kg~ -1 (calculated by carried dexamethasone). The drugs in the plasma and contents of different parts of the rats' gastrointestinal tract were determined by high performance liquid chromatography (HPLC). RESULTS: Dexamethasone carried by the prodrug was mainly released in the contents and mucosa of cecum and colon after oral administration of the prodrug. The absorption of released dexamethasone was reduced significantly. The peak time, peak concentration and AUC were 7.2 h , 42 ?g?L~ -1 and 334 ?g?h?L~ -1 , respectively. However, free dexamethasone was found mainly in the contents and mucosa of the stomach, proximal and distal small intestine after oral administration. The peak time, peak concentration and AUC were 2.2 h, 2 120 ?g?L~ -1 and 11 875 ?g?h?L~ -1 , respectively. CONCLUSION: Dexamethasone can be specifically delivered to the cecum and colon by using dexamethasone- angelica sinensis polysaccharides prodrug. The absorption of dexamethasone was reduced significantly and the drug concentration in colon was increased significantly. The prodrug has a potential in the treatment of colitis.