Study on the Relationship of Changes of Id2 Protein Expression in Diabetic Rat Kidney Tissues with Occurrence and Development of Fibrosis Lesions
Author(s): WEN Qingying, SU Bo, XIAO Ying, WANG Yuanyuan, LI Shuang, LIU Lirong, SHI Mingjun, GUO Bing
Pages: 330-336
Year: 2015 Issue: 4
Journal: Journal of Guiyang Medical College
Keyword: diabetic nephropathy; fibrosis; inhibitors of differentiation; fibronectin; E-cadherin; α-smooth muscle actin; rats; Sprague-Dawley;
Abstract: Objective:To investigate the expressions of Id2 in the renal tubules of STZ-induced dia-betic rats before and after blood glucose control,and explore their roles and relationship in the devel-opment of diabetic nephropathy.Methods:SD rats were randomly divided into control (N),diabetes mellitus (DM)and insulin-treated DMgroups (DMT).DMmodel was constructed by injecting strep-tozotocin (STZ)via tail vein (55 mg/kg).48 SD rats were randomly divided into 4 groups:2 weeks, 8 weeks,16 weeks and 24 weeks group.Each group included a control subgroup and a diabetic model subgroup.In addition,for 16 weeks group and 24 weeks group,each group still included an insulin-treated subgroup.Since the 13 th week after modeling,rats in DMT group were given insulin individual-
ly.The blood glucose was controlled to the level of 4 ~7 mmol /L,and urine glucose remained nega-tive.The blood glucose,24 h urine protein were measured by biochemical method,and the kidney in-dex was measured as well.And the renal fibrosis was examined by HE and PAS staining sections.Im-munohistochemistry was employed to assay the expression of FN protein in the rat renal tissue.Western blotting was employed to assay the expression of Id2,E-cadherin and α-SMA protein in the rat renal tissue.In addition,the expression of Id2 mRNA was also examined by RT-PCR.Results:(1)Com-pared with group N,the blood glucose,24 h urine protein and the kidney index of group DMincreased significantly (P <0.01 ),and renal tissue presented typical morphologic changes at different time points.By comparison,the blood glucose,24 h urine protein and the kidney index of group DMT were significantly lower than those in group DM(P <0.05).Lesions of renal fibrosis in DMT rats were ob-viously relieved.(2)The expression levels of Id2 protein and mRNA of group DM decreased signifi-cantly than that in N group at different time points (P <0.05),accompanied by the decreased expres-sion of E-cadherin (P <0.05),increased expression of α-SMA (P <0.05),and increased deposition of FN protein.Correlation analysis showed Id2 protein was negatively correlated with FN protein(r =-0.931,P <0.05),but positively correlated with E-cadherin(r =0.900 0,P <0.05).(3)Com-pared with DM group,the protein and mRNA expression of Id2 and E-cadherin of DMT group in-creased significantly (P <0.05),while the expression of α-SMA and FN protein decreased.Conclu-sion:Blood glucose control can up-regulate the expression of Id2 in renal tubular epithelial cells and restore Id2 negative regulation of renal fibrosis,reverse EMT and relieve renal interstitial ECMdeposi-tion,and improve DN lesions of renal fibrosis.
Pages: 330-336
Year: 2015 Issue: 4
Journal: Journal of Guiyang Medical College
Keyword: diabetic nephropathy; fibrosis; inhibitors of differentiation; fibronectin; E-cadherin; α-smooth muscle actin; rats; Sprague-Dawley;
Abstract: Objective:To investigate the expressions of Id2 in the renal tubules of STZ-induced dia-betic rats before and after blood glucose control,and explore their roles and relationship in the devel-opment of diabetic nephropathy.Methods:SD rats were randomly divided into control (N),diabetes mellitus (DM)and insulin-treated DMgroups (DMT).DMmodel was constructed by injecting strep-tozotocin (STZ)via tail vein (55 mg/kg).48 SD rats were randomly divided into 4 groups:2 weeks, 8 weeks,16 weeks and 24 weeks group.Each group included a control subgroup and a diabetic model subgroup.In addition,for 16 weeks group and 24 weeks group,each group still included an insulin-treated subgroup.Since the 13 th week after modeling,rats in DMT group were given insulin individual-
ly.The blood glucose was controlled to the level of 4 ~7 mmol /L,and urine glucose remained nega-tive.The blood glucose,24 h urine protein were measured by biochemical method,and the kidney in-dex was measured as well.And the renal fibrosis was examined by HE and PAS staining sections.Im-munohistochemistry was employed to assay the expression of FN protein in the rat renal tissue.Western blotting was employed to assay the expression of Id2,E-cadherin and α-SMA protein in the rat renal tissue.In addition,the expression of Id2 mRNA was also examined by RT-PCR.Results:(1)Com-pared with group N,the blood glucose,24 h urine protein and the kidney index of group DMincreased significantly (P <0.01 ),and renal tissue presented typical morphologic changes at different time points.By comparison,the blood glucose,24 h urine protein and the kidney index of group DMT were significantly lower than those in group DM(P <0.05).Lesions of renal fibrosis in DMT rats were ob-viously relieved.(2)The expression levels of Id2 protein and mRNA of group DM decreased signifi-cantly than that in N group at different time points (P <0.05),accompanied by the decreased expres-sion of E-cadherin (P <0.05),increased expression of α-SMA (P <0.05),and increased deposition of FN protein.Correlation analysis showed Id2 protein was negatively correlated with FN protein(r =-0.931,P <0.05),but positively correlated with E-cadherin(r =0.900 0,P <0.05).(3)Com-pared with DM group,the protein and mRNA expression of Id2 and E-cadherin of DMT group in-creased significantly (P <0.05),while the expression of α-SMA and FN protein decreased.Conclu-sion:Blood glucose control can up-regulate the expression of Id2 in renal tubular epithelial cells and restore Id2 negative regulation of renal fibrosis,reverse EMT and relieve renal interstitial ECMdeposi-tion,and improve DN lesions of renal fibrosis.
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