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Objective: To investigate the effect of AG490, a Janus kinase 2 inhibitor, on epithelial-myofibroblast transdifferentiation induced by interleukin-1β (IL-1β)., Methods: Cultured human renal tubular epithelial cell line (HKCs) were divided into three groups: blank control group, IL-1β (5 ng/ml) group and AG490 group (IL-1β 5 ng/ml+AG490 10 μmol/L). The cells in all groups were collected at 24, 48, 72 hours after intervention. Immunocytochemistry and Western blotting analysis were used to determine the expressions of cytokeratin-18 (CK-18) and α-smooth muscle actin (α-SMA)., Results: The higher expression of CK-18 (1.25±0.08) and mild expression of α-SMA (0.17±0.01) were found in blank control group. In IL-1β group, the protein level of CK-18 was gradually decreased with prolongation of stimulus (24 hours : 0.69±0.04, 48 hours: 0.52±0.03, 72 hours: 0.30±0.01), while the expression level of α-SMA was gradually increased (24 hours: 0.56±0.04, 48 hours: 1.05±0.07, 72 hours: 1.43±0.07), and the difference between blank control group and IL-1β group was statistically significant (all P<0.05). The administration of AG490 could restore the expression of CK-18 (24 hours: 1.07±0.07, 48 hours: 0.93±0.06, 72 hours: 0.83±0.06), and inhibit the expression of α-SMA induced by IL-1β (24 hours: 0.33± 0.01, 48 hours: 0.52±0.01, 72 hours: 0.61±0.04). There was significant difference between AG490 group and IL-1β group (all P<0.05). The results of immunocytochemistry and that of Western blotting were identical., Conclusion: IL-1β can induce the transdifferentiation of renal tubular epithelial cells, up-regulate the expression of α-SMA, induce the renal tubular epithelial cells to transform to myofibroblast, while AG490 can inhibit the effect of IL-1β.

Objective: To explore the effect of high fat diet on the expression of sterol regulatory element binding protein-1 (SREBP-1), transforming growth factor-beta1 (TGF-beta1) and alpha-smooth muscle actin (alpha-SMA) in renal tubular cells and extracellular matrix accumulation in Wistar rats., Methods: The Wistar rats were treated with high fat diet for 12 weeks and renal lipid deposit was detected by the method of Oil Red O staining. The immunohistochemistry and Western blot were used to investigate the expression of SREBP-1, TGF-beta1, alpha-SMA and fibronectin (FN) protein. The expression of SREBP-1 mRNA was determined with in situ hybridization. Masson staining was for the detection of extracellular matrix (ECM) accumulation., Results: The weight of rats raised by high fat diet increased, in company with the high serum glucose, serum triglyceride and serum insulin. The Oil Red O staining revealed that the renal proximal tubular epithelial cells showed significant lipid droplet in high fat diet rats. SREBP-1 protein and mRNA were located in the renal tubular cells and the expressions of high fat diet rats were higher than those of normal control rats. They were respectively 1.88 times and 1.85 times than those of normal control group. TGF-beta1 and alpha-SMA protein were also located in renal tubular cells and high fat diet up-regulated the expression of them. ECM accumulation was detected with Masson staining and the result showed that high fat diet treatment increased interstitial ECM product and FN protein was found high expression., Conclusion: High fat diet may induce lipid droplet deposit in renal tubular cells by up-regulation of the expression of SREBP-1, which causes ECM accumulation by increasing the expression of TGF-beta1 and alpha-SMA.

Objective: To investigate the expression of cyclooxygenase-2 (COX-2), human mut-l homologue 1 (hMLH1) and human mut-s homologue 2 (hMSH2) proteins in human paired gastric carcinoma (GC) and adjacent normal mucosa, and analyze their relationship with microsatellite instability (MSI)., Methods: The protein expressions were examined by western blotting. Five MSI loci were assessed by PCR., Results: In 30 surgically excised GC tissues, the overexpression rate of COX-2, the low expression rate of hMLH1 and hMSH2 were 66.7%, 40% and 33.3%, respectively. Significant differences were found when compared with those of adjacent normal mucosa (P < 0.05). MSI was detected in 13 GC. The number of MSI-H (MSI-High, > or = 2 loci), MSI-L (MSI-Low, only one locus), and MSS (microsatellite stable) were 9, 4 and 17, respectively. The number of low expression rates of COX-2, hMLH1 and hMSH2 in MSI-H were 6, 8 and 5, respectively. There were significant differences compared to that of MSS (P < 0.05)., Conclusion: The results suggest that microsatellite instability pathway is probably involved in the carcinogenesis of gastric carcinoma, which is frequently accompanied by low expression of hMLH1 and hMSH2, and may be also by low expression of COX-2.