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.

Effect of respiratory syncytial virus on the activity of matrix metalloproteinase in mice

Background Respiratory syncytial virus （RSV） is a common pathogen in the lower respiratory tract of infants and children. Recent studies have shown that in adults, especially in the eldedy population who have relatively weak immunity, lower respiratory tract infection is not uncommon. RSV was detected in 22% hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease （COPD）, and the detection rate was only next to that of parvovirus and influenza virus respectively. Further studies revealed that lung infection of RSV could lead to inflammatory destruction and structural remodeling. This study was undertaken to examine the effect of infection with RSV on matrix metalloproteinase （MMPs） in mice, and to explore the role of RSV in the pathogenesis of pulmonary diseases. Methods Twenty BALB/c mice were divided randomly into an RSV infection group and a blank control group. The mice in the RSV infection group were given 100 pl liquid containing 10s PFU of RSV by intranasal instillation. Three days after the infection, the bronchoalveolar lavage fluid （BALF） was harvested and RT-PCR and Western blotting were used to detect MMP-9 and the expression of tissue inhibitors of matdx metalloproteinase （TIMP）-I mRNA in lung tissues. Gelatin zymography was employed to detect the activities of MMP-9 and MMP-2 in BALF. Immunohistochemistry was used to determine the expressions of E-cadherin （E-cd） and proliferating call nuclear antigen （PCNA） in the lung tissues. Results In the BALF of the mice infected with RSV, the activities of MMP-9 and MMP-2 were significantly increased （t=-6.08, P〈0.01 and t=5.68, P〈0.01）. The levels of mRNAand proteins of MMP-9 in the lung tissues of the mica infected with RSV were significantly elevated, and the mRNA and protein levels were significantly higher than those of the blank controls. Though the ratio of MMP-9/TIMP-1 mRNA in the lung tissues of the infected mica was not significantly different from that of the normal controls, the ratio of the MMP-9/TIMP-1 protein in the RSV infection group was significantly higher than that in the control group. Moreover, the number of cells with positive E-cd expression was decreased and the number of calls positive for PCNA was increased, with an enhanced expression. Conclusions In mica, infection with RSV can significantly increase the activities of MMP-9 and MMP-2, and conspicuously elevate the mRNA transcription of MMP-9. RSV infection can increase the activity of gelatinase while up-regulating its inhibitory factors but increase its protein ratio of MMP-9/TIMP-1 in lung tissues, thereby facilitating fibrosis after structural destruction of the airway. The resultant status might be an important factor causing chronic reconstruction of the airway.