OBJECTIVETo investigate the effect of tea polyphenols on cell apoptosis in rat model of cyclosporine-induced chronic nephrotoxicity.

METHODSFour groups of animals in rat model of cyclosporine-induced chronic nephrotoxicity were respectively treated by olive oil (n = 6), tea polyphenols (TP, n = 6), cyclosporine A (CsA, n = 8) and TP plus CsA (n = 8). At the end of 28th day of treatment, all animals were sacrificed and blood was analyzed for blood serum creatinine and creatinine clearance, kidney tissue for pathologic analysis. The TUNEL assay, caspase-3 mRNA expression detected by reverse transcription-polymerase chain reaction (RT-PCR) and caspase-3 activity were used for the analysis of cell apoptosis.

RESULTSCsA plus TP ameliorated the CsA-induced decrease of renal function and interstitial fibrosis. There was a significant increase in the number of apoptosis-positive cells in the CsA-vs-CsA plus TP-treated group at four weeks (18.9 +/- 3.3 vs. 7.7 +/- 1.4, P < 0.05). The expression of caspase-3 mRNA and caspase-3 activity of CsA-treated group was significantly higher than that of CsA plus TP-treated group (P < 0.05).

CONCLUSIONThese results indicate that antioxidant tea polyphenols significantly inhibit apoptosis of tubular and interstitial cells in rat model of chronic cyclosporine-induced nephrotoxicity, and suggest that the decrease of cell apoptosis exerted by tea polyphenols may be one of mechanisms to protect renal function and tissue structure.

Animals ; Antioxidants ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; Caspases ; genetics ; Cyclosporine ; toxicity ; Flavonoids ; Immunosuppressive Agents ; toxicity ; In Situ Nick-End Labeling ; Kidney ; drug effects ; Male ; Phenols ; pharmacology ; Polymers ; pharmacology ; Polyphenols ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Tea

The pathogenesis of chronic cyclosporine A (CsA) nephrotoxicity has not been elucidated, but apoptosis is thought to play an important role in CsA induced tubular atrophy. Recently Fas-Fas ligand system mediated apoptosis has been frequently reported in many epithelial cells as well as in T lymphocytes. We investigated the ability of CsA to induce apoptosis in cultured human proximal tubular epithelial cells and also the effect of -MSH on them. Fas, Fas ligand, and an intracellular adaptor protein, Fas-associating protein with death domain (FADD) expression, and poly-ADP ribose polymerase (PARP) cleavage were also studied. CsA induced apoptosis in cultured tubular epithelial cells demonstrated by increased number of TUNEL positive cells and it was accompanied by a significant increase in Fas mRNA and Fas ligand protein expressions. FADD and the cleavage product of PARP also increased, indicating the activation of caspase. In -MSH co-treated cells, apoptosis markedly decreased with downregulation of Fas, Fas ligand and FADD expressions and also the cleavage product of PARP. In conclusion, these data suggest that tubular cell apoptosis mediated by Fas system may play a role in tubular atrophy in chronic CsA nephrotoxicity and pretreatment of -MSH may have a some inhibitory effect on CsA induced tubular cell apoptosis.
Antigens, CD95/genetics ; Apoptosis/*drug effects ; Carrier Proteins/biosynthesis ; Caspases/physiology ; Cells, Cultured ; Cyclosporine/*toxicity ; Human ; Immunosuppressive Agents/*toxicity ; Kidney Tubules, Proximal/cytology/*drug effects/metabolism ; Membrane Glycoproteins/biosynthesis ; NAD+ ADP-Ribosyltransferase/metabolism ; RNA, Messenger/analysis ; alpha-MSH/*pharmacology

Sirolimus (SRL) is a promising drug for replacing calcineurin inhibitors. We performed this study to determine the optimal time of conversion from cyclosporine (CsA) to SRL in an experimental model of chronic CsA nephropathy. Three separate studies were performed. In the first study, SRL was given to rats with or without CsA for 4 weeks. In the second study, rats were treated initially with CsA for 1 week, and then switched to SRL (early conversion). In the third study, CsA was given for 4 weeks and then replaced by SRL for 4 weeks treatment of CsA (late conversion). The influence of SRL on CsA-induced renal injury was evaluated by assessing renal function, histopathology (interstitial inflammation and fibrosis), and apoptotic cell death. Combined CsA and SRL treatment significantly impaired renal function, increased apoptosis, and interstitial fibrosis and inflammation compared with CsA or SRL treatment alone. Early conversion to SRL did not change renal function, histopathology, or apoptosis compared with early CsA withdrawal. By contrast, late conversion to SRL significantly aggravated these parameters compared with late CsA withdrawal. In conclusion, early conversion from CsA to SRL is effective in preventing CsA-induced renal injury in a setting of CsA-induced renal injury.
Animals ; Apoptosis/drug effects ; Chronic Disease ; Cyclosporine/*toxicity ; Immunosuppressive Agents/*pharmacology ; Intestines/drug effects/pathology ; Kidney Diseases/chemically induced/*pathology ; Male ; Models, Animal ; Rats ; Rats, Sprague-Dawley ; Sirolimus/*pharmacology

PURPOSE: We recently reported that rosiglitazone (RGTZ), a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, has a protective effect against cyclosporine (CsA)- induced renal injury. Here we report the effect of RGTZ on peroxisome proliferator-activated receptor gamma (PPARgamma) expression in an experimental model of chronic cyclosporine (CsA) nephropathy. MATERIALS AND METHODS: Chronic CsA nephropathy was induced in Sprague-Dawley rats by administering CsA (15mg/kg per day) for 28 days, and control rats were treated with vehicle (VH group, olive oil 1mL/kg per day) for 28 days. RGTZ (3mg/kg) was concurrently administered via gavage to the CsA and VH groups. Expression of PPARgamma mRNA and protein was evaluated with RT-PCR, immunohistochemistry, and immunoblotting. RESULTS: PPARgamma mRNA expression was similar to the level of PPARgamma protein constitutively expressed in the kidneys of the VH treated rats, with expression in the glomerular epithelial, distal tubular cells, and collecting tubular cells. PPARgamma protein expression in CsA-treated rat kidneys was significantly less than in the VH group. However, concomitant administration of RGTZ restored PPARgamma protein expression in the kidneys of the CsA- reated rats. CONCLUSION: Exogenous administration of RGTZ treatment upregulates PPARgamma expression and that this mechanism may play a role in protecting against CsA-induced renal injury.
Transcription, Genetic/*drug effects ; Thiazolidinediones/*pharmacology ; Rats, Sprague-Dawley ; Rats ; RNA, Messenger/*genetics ; Protein Biosynthesis/*drug effects ; PPAR gamma/*genetics ; Male ; Kidney Diseases/genetics/pathology/*prevention & control ; Gene Expression Regulation/*drug effects ; Disease Models, Animal ; Cyclosporine/*toxicity ; Animals

OBJECTIVETo investigate the gene expression of MAPEG in the cortex of concanavalin A (Con A)-induced mouse immune inflammatory model and the effect of cyclosporine A (Cs A).

METHODSMale Balb/c mouse immune inflammation model was developed by intravenous injection of Con A (20 mg/kg). Cs A (150 mg/kg) was intravenously infected prior to Con A administration. The MAPEG expressions were determined by RT-PCR.

RESULTmGST1, mGST3, LTC(4)S, FLAP and mPGES-1 were detected by RT-PCR but not mGST2. Eight hours after Con A treatment, mGST1 level was up-regulated to 1.2 approximately 1.5 folds of control with or without Cs A treatment. mGST3ìLTC(4)S, FLAP and mPGES-1 mRNA levels were not influenced by Con A administration.

CONCLUSIONImmune mechanism may be not involved in mGST1 up-regulation in this model and Con A does not alter arachidonic acid metabolism in cortex.

5-Lipoxygenase-Activating Proteins ; Animals ; Brain ; metabolism ; Carrier Proteins ; genetics ; metabolism ; Concanavalin A ; toxicity ; Cyclosporine ; pharmacology ; Eicosanoids ; metabolism ; Glutathione ; metabolism ; Glutathione Transferase ; genetics ; metabolism ; Intramolecular Oxidoreductases ; genetics ; metabolism ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Prostaglandin-E Synthases

BACKGROUND/AIMS: Hypoalbuminemia occurs frequently in renal transplant recipients immediately after renal transplantation. We studied the regulation of hepatic albumin synthesis by cyclosporin A (CsA) in Huh7 cells. METHODS: Huh7 cells were incubated with various concentrations of CsA for 4, 8, 16, and 24 hours. Albumin was measured in Huh7 cell-conditioned medium by sandwich enzyme-linked immunosorbent assay and Western blot. Albumin mRNA expression was analyzed by Northern blotting in CsA-treated cells. RESULTS: CsA (10(-7)-10(-4) M) inhibited albumin synthesis in Huh7 cells in a dose- dependent manner. A Western blot analysis for albumin in the conditioned medium released from CsA-treated (10(-7)-10(-5) M) cells also showed significant inhibition of albumin synthesis in a dose-dependent manner. Vehicle (olive oil) did not affect albumin synthesis. In contrast, a Northern blot analysis revealed no inhibition of albumin mRNA expression by CsA at any time point from 1-24 hours, indicating that the inhibition of albumin synthesis occurred at the translational level. CONCLUSIONS: Our results suggest that inhibition of hepatic albumin synthesis by high dose CsA contributes to the hypoalbuminemia in renal transplant recipients.
Blotting, Northern ; Blotting, Western ; Carcinoma, Hepatocellular/genetics/*metabolism ; Cell Line, Tumor ; Cell Survival/drug effects ; Culture Media, Conditioned/metabolism ; Cyclosporine/*pharmacology/toxicity ; Dose-Response Relationship, Drug ; Enzyme-Linked Immunosorbent Assay ; Gene Expression Regulation, Neoplastic/drug effects ; Humans ; Hypoalbuminemia/chemically induced/metabolism ; Immunosuppressive Agents/*pharmacology/toxicity ; Liver Neoplasms/genetics/*metabolism ; RNA, Messenger/metabolism ; Serum Albumin/genetics/*metabolism ; Time Factors

Cyclosporin A (CsA)-induced hyperkalemia is caused by alterations in transepithelial K(+) secretion resulting from the inhibition of renal tubular Na(+), K(+) -ATPase activity. Thyroxine enhances renal cortical Na(+), K(+) -ATPase activity. This study investigated the effect of thyroxine on CsA-induced hyperkalemia. Sprague-Dawley rats were treated with either CsA, thyroxine, CsA and thyroxine, or olive-oil vehicle. CsA resulted in an increase in BUN and serum K(+), along with a decrease in creatinine clearance, fractional excretion of potassium, and renal cortical Na(+), K(+) -ATPase activity, as compared with oil vehicle administration. Histochemical study showed reduced Na(+), K(+) -ATPase activity in the proximal tubular epithelial cells of the CsA-treated compared with the oil-treated rats. Histologically, isometric intracytoplasmic vacuolation, disruption of the arrangement and swelling of the mitochondria, and a large number of lysosomes in the tubular epithelium were characteristic of the CsA-treated rats. Co-administration of thyroxine prevented CsA-induced hyperkalemia and reduced creatinine clearance, Na(+), K(+) -ATPase activity, and severity of the histologic changes in the renal tubular cells when compared with the CsA-treated rats. Thyroxine increased the fractional excretion of potassium via the preservation of Na(+), K(+) -ATPase activity in the renal tubular cells. Thus, the beneficial effects of thyroxine may be suited to treatment modalities for CsA-induced hyperkalemia.
Animals ; Cyclosporine/antagonists & inhibitors/*toxicity ; Hyperkalemia/chemically induced/*drug therapy/metabolism/prevention & control ; Immunosuppressive Agents/antagonists & inhibitors/*toxicity ; Kidney Cortex/*drug effects/*enzymology/pathology ; Male ; Microsomes/enzymology ; Potassium/blood/metabolism ; Rats ; Rats, Sprague-Dawley ; Sodium-Potassium-Exchanging ATPase/*metabolism ; Thyroxine/*pharmacology

OBJECTIVETo explore the gene expressions of LTC4 synthase homologs in concanavalin A (Con A)-induced mouse hepatitis and regulation role of cyclosporine A (Cs A) treatment.

METHODSMale Balb/c mouse liver injury model was developed by iv injection of Con A (20 mg/kg) and protected by Cs A pretreatment (150 mg/kg) before Con A administration. Blood samples were collected at indicated times after Con A treatment with or without Cs A pretreatment. Liver damage was assessed by serum transaminase ALT and AST measurement and histological evaluation. Meantime, three LTC4 synthase homolog gene expressions were determined by RT-PCR.

RESULTSSerum ALT and AST upregulation were accompanied with histological damage at 2 h after Con A administration, and further aggravated at 8 h. mGST2 gene expression increased 1.7 fold at 2 h and 1.9 fold at 8 h, while the expression of LTC4 S and mGST3 changed little. Pretreatment with Cs A prevented mouse liver from injury by Con A and partly inhibited the mGST2 gene expression upregulation.

CONCLUSIONSAdministration of Con A in mouse lead to a significant increase of mGST2 gene expression without any significant effect on LTC4 S and mGST3 mRNA levels. Cs A pretreatment results in protection of liver damage, whereas fails to fully inhibit the increase of mGST2 gene expression.

Alanine Transaminase ; blood ; Animals ; Aspartate Aminotransferases ; blood ; Chemical and Drug Induced Liver Injury ; enzymology ; etiology ; prevention & control ; Concanavalin A ; administration & dosage ; toxicity ; Cyclosporine ; pharmacology ; Gene Expression Regulation, Enzymologic ; genetics ; Glutathione Transferase ; genetics ; Hepatitis, Animal ; chemically induced ; enzymology ; prevention & control ; Immunosuppressive Agents ; pharmacology ; Injections, Intravenous ; Isoenzymes ; genetics ; Male ; Mice ; Mice, Inbred BALB C ; Reverse Transcriptase Polymerase Chain Reaction