THE LOCALIZATION OF ADRENOMEDULLIN IN RAT KIDNEY TISSUE AND ITS INHIBITORY EFFECT ON THE GROWTH OF CULTURED RAT MESANGIAL CELLS

OBJECTIVE: To observe the localization of adrenomedullin (AM) in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells (MsC). METHODS: A monoclonal antibody against AM developed by our laboratory was used to detect the localization of AM protein in rat kidney tissue by avidin-biotin complex immunohistochemistry. The expressions of AM and its receptor CRLR mRNA on cultured glomerular epithelial cells (GEC) and MsC were investigated by Northern blot assay, and the possible effect of AM secreted by GEC on MsC proliferation was observed using [3H]thymidine incorporation as an index. RESULTS: A specific monoclonal antibody against AM was succesfully developed. AM was immunohistochemically localized mainly in glomeruli (GEC and endothelial cells), some cortical proximal tubules, medullary collecting duct cells, interstitial cells, vascular smooth muscle cells and endothelial cells. Northern blot assay showed that AM mRNA was expressed only on cultured GEC, but not on MsC, however, AM receptor CRLR mRNA was only expressed on MsC. GEC conditioned medium containing AM can inhibit MsC growth and AM receptor blocker CGRP8-37 may partially decreased this inhibitory effect. CONCLUSION: AM produced by GEC inhibits the proliferation of MsC, which suggests that AM as an important regulator is involved in glomerular normal physiological functions and pathologic processes.

Cytotoxic Responses and Apoptosis in Rat Kidney Epithelial Cells Exposed to Lead

The toxic effects of lead on normal rat kidney epithelial cells（NRK cells）may occur via various pathways.However,the role of intrinsic mitochondrial pathway in Lead-induced apoptosis in NRK cells has not been investigated.The purpose of our study was to investigate cytotoxic responses and cell apoptosis mediated by lead in NRK cells.

EN BLOC TRANSPLATION OF KIDNEY AND WHOLE PANCREAS WITH A SEGMENT OF DUODENUM IN RATS

For meeting the clinic needs in simultaneous pancreas and kidney transplantation (SPK), we success-fully establish a syngeneic SPK transplatation model in Lewis rats. The results indicate that this model isfeasible with a 82. 6% successful rate of operation and a 69. 6% survival rate in the first postoperativeweek. In long-term survived rats, the blood supplies are well established, function of the grafts (pancreasand kidney) maintains normal. This model is suitable for theoretical reserach in SPK transplantation for itsreasonable physiology with pancreatic juice drained into intestine and reduced postoperative complications inurinary tract and carbohydrate metabolism.

Effects of polar cortical cytoskeleton and unbalanced cortical surface tension on intercellular bridge thinning during cytokinesis

To probe the contributions of polar cortical cytoskeleton and the surface tension of daughter cells to intercellular bridge thinning dynamics during cytokinesis,we applied cytochalasin D（CD） or colchicine（COLC） in a highly localized manner to polar regions of dividing normal rat kidney（NRK） cells.We observed cellular morphological changes and analyzed the intercellular bridge thinning trajectories of dividing cells with different polar cortical characteristics.Global blebbistatin（BS） application was used to obtain cells losing active contractile force groups.Our results show that locally released CD or colchicine at the polar region caused inhibition of cytokinesis before ingression.Similar treatment at phases after ingression allowed completion of cytokinesis but dramatically influenced the trajectories of intercellular bridge thinning.Disturbing single polar cortical actin induced transformation of the intercellular bridge thinning process,and polar cortical tension controlled deformation time of intercellular bridges.Our study provides a feasible framework to induce and analyze the effects of local changes in mechanical properties of cellular components on single cellular cytokinesis.

Inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine-induced chronic nephrotoxicity

Objective To investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA)-induced chronic nephrotoxicity.Methods Four groups of rats with CsA-induced chronic nephrotoxicity were respectively treated with vehicle olive oil, tea polyphenols, CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were analysed for creatinine clearance, and kidney tissue was used for pathologic analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis.Results CsA-treated rats displayed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18. 3±4. 6 vs 4. 8±1.3 cells/mm2, P < 0. 05 ) . In comparision with animals treated by CsA, animals treated with CsA plus tea polyphenols demonstrated significantly improved levels of creatinine clearance (0. 12 ±0. 03 vs 0. 22±0. 02 ml ·min-1·100g-1 body weight, P < 0. 05), tubular injury (2. 29 ±0. 43 vs 1. 42±0. 26, P < 0. 05), and interstitial fibrosis (2. 83±0. 20 vs 1. 46±0. 19, P <0. 05), and showed a statistically significant decrease in tubular and interstitial cell apoptosis (18. 3±4. 6 vs 7. 7±2.1 cells/mm2, P<0. 05). The expression of caspase-3 mRNA and caspase-3 activity was significantly higher in the CsA-treated group than that of the CsA plus tea polyphenols (TP)-treated group (P<0. 05).Conclusion These results suggested that tea polyphenols significantly inhibits apoptosis of the tubular and interstitial cells in rats with cyclosporine-induced chronic nephrotoxicity, and that tea polyphenols may be useful to prevent CsA-associated kidney toxicity.