| Objective:To explore whether curcumin(CMN) could induce the expression of heme oxygenase-1 (HO-1) in rat's kidney and prevent against contrast-induced nephropathy by inducing HO-1 expression. Methods:24 male SD rats aged 4 months were divided randomly into control group(Group A,n=6), diatrizoate(DTZ) group(Group B, n=6), DTZ+CMN group (GroupC,n=6),DTZ+CMN+zinc protoporphyrinⅨ(ZnPPⅨ) group (Group D,n=6).The experimental time is 6 weeks. There were 4 steps in our experiment. 1. The establishment of rat CIN model. The right kidney of all the rats was resected under general anesthesia after compatibility feeds for 1 week, all the rats were continuously fed with general food for 4 week. In the sixth week, rats in group A still fed with general food while the other three groups were fed with salt-free food and all the rats were injected intramuscularly with furosemide 2mg/kg once a day.At the end of sixth week, indometacin lOmg/kg were injected into rat's tail vein in each group,an hour later,60% diatrizoate(8mL/kg) was injected into one side common carotid artery of rats in the Group B,C and D(in 2 minutes) while rats in Group A were injected with the same amount of saline.The follow 24 hours urine was collected for checking the quantity of urine protein, Serum creatinine was measured to evaluate CIN model establishment effect till 48 hours later.2. HO-1 protein expression and HO-1 activity affected by medicine intervention.24 hours before the diatrizoate injection,rats in Group C and Group D were injected intraperitonealy respectively with CMN 30mg/kg and CMN 30mg/kg+ZnPPⅨ7.5mg/kg while rats in Group A and Group B were injected with the same amount of saline.48 hours After diatrizoate injection, rats were killed and the kidney was taken to detect the HO-1 protein expression by western blotting analysis, HO-1 activity was determinated by measuring the amount of bilirubin which was the product of heme degenerated by the HO-1. The results of HO-1 expression and HO-1 activity in different goups were compared.3.To explore the effects and mechanism of inducing/inhibiting the HO-1 protein expression to the CIN. Just after the rats were killed, The blood was drawn via heart from all rats in each group and used to test renal function. Part of the renal tissue was used to test interleukin-6 (IL-6),Malondialdehyde (MDA), Monocyte chemoattractant protein-1 (MCP-1), Bax, Bcl-2 and the apoptotic index, The results of these parameters in each group were compared. Another part of the renal tissue were used for histopathological detection.Result:1. The CIN model of rats was successfully established. Compared with rats in Group A, Serum creatinine (Cr) of rats in Group B increased significantly which was consistent in the clinical trial definition about CIN—《2007 Chinese expert consensus of contrast-induced nephropathy》.Namely, Serum creatinine increased by 0.5mg/mL (44.2umol/L) or higher than the basal value of 25% within 48 hours after application of iodine contrast agents.2. Compared to Group A, HO-1 expression increased significantly in Group B,D,C (P<0.05 respectively). Compared the difference among Group B,C,D, HO-1 protein expression and HO-1 activity were increased significantly in Group C(P<0.05 respectively), relevant renal damage was significantly reduced.HO-1 protein expression in Group B was much the same as Group D, but HO-1 activity was lower markedly, relevant renal damage was the most serious among the four groups.3. IL-6, MDA, MCP-1, Bax, Bcl-2 and apoptotic index in Group B,C,D were statistically different compared to that in Group A. However, compared the difference among Group B,C,D, IL-6, MDA, MCP-1, Bax and apoptotic index in Group C was significantly lower than that of Group B, Bcl-2 was significantly higher than that of Group B. IL-6, MDA, MCP-1, Bax and apoptotic index in Group D was increased significantly than that of Group B, Bcl-2 was decreased significantly than that of Group B. Conclusion:1.CIN model could be successfully established in rats.2.CMN could induce HO-1 protein expression and increase HO-1 activity in rats'kidney,which can be blocked by ZnPPⅨ.3. CMN preventing against CIN were mainly mediated by HO-1 expression.4.Anti-inflammation, anti-oxidative stress and inhibitting cell apoptosis might be the major renal protecting mechanism of HO-1.
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