The Positive Impact Of Active Vitamin D3 On It’s Receptor And Renal Fibrosis Factors In Diabetic Nephropathy Rats

Objective:To determine the role and possible mechanisms of active vitamin D3(1, 25-dihydroxy vitamin D3)on vitamin D receptor(VDR) and renal fibrosis in diabetic nephropathy.Methods:Diabetic nephropathy were induced by intraperitoneal injection of STZ. Different gradient expressions of TGF-β1 were established by injection of different types of lentivirus with TGF-(31. DN rats(n=36) were randomly divided into 6 groups: ① TGF-β1 over-expression with arachis oil group(n=6);② TGF-β1 over-expression with active vitamin D3 group(n=6),③ TGF-β1 low-expression with arachis oil group(n=6), ④ TGF-β1 low-expression with active vitamin D3 group(n=4),⑤TGF-β1 normal-expression with arachis oil group(n=6),⑥TGF-β1 normal-expression with active vitamin D3 group(n=6). The structure and morphology change in kidney tissue was observed by electron microscope;the mRNA expression of transforming growth factor(TGF-β1), vitamin D receptor(VDR), moynocte chemoattractant protein-1(MCP-1), collagen-1 (Col-1) in kidney were measured by real-time PCR.Results:(1)Kidney tissues morphology changes reduced in the groups with active vitamin D3 treatment, compared with all arachis oil group. (2)The severity of renal fibrosis is associated with the expression of TGF-β1, and the fibrosis of kidney is relieved after active vitamin D3 treatment in MASSON staining, electronic microscope and histochemistry. (3)Compared with normal-expression+arachis oil group, the expression of TGF-β1, MCP-1 and Col-1 is significantly increased and VDR level is decreased in over-expression+arachis oil groups (P<0.05); while the expression of TGF-β1,MCP-1 and Col-1 is significantly decreased and VDR level is increased in low-expression+arachis oil group(P<0.05).(4)Compared with the groups of arachis oil, the expressions of TGF-β1, MCP-1 and Col-1 are decreased, while VDR expression in all vitamin D groups is increased.Conclusion:With different gradient expression of TGF-β1 in kidney, active vitamin D3 may play a protective role in diabetic nephropathy, via negatively regulating the expression of renal fibrosis factors, such as TGF-β1, MCP-1 and Col-1 and increasing the expression of it.