PTHrP Takes Part In The Modulation Of Oxidative Stress And Inflammation In Diabetic Nephropathy

Objective:It is previously demonstrated that PTHrP(1-34)has different effects on diabetic nephropathy.With acute treatment,it suppressed the progression of diabetic nephropathy in SD rats through supressed TGFβ.But with chronic treatment,it enhanced the progression of diabetic nephropathy through activated TGFβ.It is reported that ROS and the inflammation-related molecules induced the progression of diabetic nephropathy.It is unknown that whether PTHrP(1-34)enhance the expression of ROS and the inflammation-related molecules.So,we cultured the mesangial cells and made the mode of type 1 diabetic nephropathy which was induced by STZ in order to study whether PTHrP(1-34)enhance the expression of ROS and the inflammation-related molecules.Methods:1.We used PTHrP(1-34)to treat mesangial cells in different time and then observe whether the expression of IL-1β,TNFa and subunit of NAPDH oxidases p47phox were increased.Firstly,we used PTHrP to treat mesangial cell 1h,3h,6h,12h and 24h respectively.Then,extracted total protein from cell and observed whether the expression of p47phox,IL-1β and TNFa were increased through Western blot.2.We used high glucose(HG,30 mmol/L)to treat mesangial cells in different time.Then we extracted total protein from cell and observed whether the expression of IL-1β,TNFa and p47phox were increased through Western blot.3.We observed whether PTHrP(1-34)influenced the expression of IL-1β,TNFa and p47phox in the cell treated by HG.Then,we pretreated cell by PTHrP(1-34).After that,we treated cell by HG 1h,3h,6h and 24h respectively.4.We made the mode of diabetic rat and selected they were control,diabetics,treated by low dose(40mg/kg),treated by middle dose(80mg/kg)and treated by high dose(160mg/kg).Then,we used PTHrP(1-34)treated them 15 days and 90 days respectively and then extracted total protein from cell and observed whether the expression of IL-1β,TNFα and p47phox were increased through Western blot.5.The method that make the mode of diabetic rat same as 4,then observed whether the expression of IL-1β and TNFa were increased through immunohistochemistry.Results:1.The expression of p47phox were increased after the mesangial cells were treated by HG for 3 hours.PTHrP(1-34)treatment for 6 hours induced the increased expression of p47phox.2.The expression of IL-10 was increased after the mesangial cells were treated by HG for 6 hours.PTHrP(1-34)treatment for 12 hours induced the increased expression of IL-1β.3.The expression of TNFa was increased after the mesangial cells were treated by HG for 1 hour.PTHrP(1-34)treatment for 3 hours induced the increased expression of TNFa.4.The pretreatment of PTHrP(1-34)inhibited the increased expression of p47phox and TNFa treated by HG within 3 hours but did not inhibit the increased expression of p47phox treated and TNFa by HG for 24 hours.The pretreatment of PTHrP(1-34)had no effect on HG-induced IL-1β upregulation.5.The expression of p47phox,IL-1β and TNFa was inhibited by different doses of PTHrP(1-34)in kidney of diabetic rat for 15 days,but was not prevented by different doses of PTHrP(1-34)in kidney of diabetic rat for 90 days.Conclusion:It is suggested that short-term treating by PTHrP(1-34)inhibited the production of NADPH oxidase NOX1 and NOX2,resulted in the reduced expression of IL-1β and TNFain diabetic rat kidney.The results were adverse if PTHrP(1-34)treated in long term.This is similar to the different effect of TGFβ.It is proved that PTHrP(1-34)has new effect independent of high glucose in the progression of diabetic nephropathy.