ABSTRACT
Objective To investigate the effect of silment information regulator factor related enzymes 1 (SIRT1) on the apoptosis of retinal ganglion cells (RGCs) in rats with diabetic retinopathy and its downstream molecular mechanisms.Methods Together 60 healthy male Sprague-Dawley rats were collected and randomly divided into normal group,diabetic group,SIRTI activator-resveratrol treatment group (treatment group),and diabetic rat model was induced by intraperitoneal injection of streptozotocin at 60 mg · kg-1 in the latter two group rats,while the normal group was injected with sodium citrate buffer at 60 mg · kg-1.Then,after 72 h,rats with blood glucose ＞ 16.7 mmol · L-1 were designated as diabetic rats by blood glucose test.Then each rat in the treatment group was treated with SIRT1 activator-resveratrol at 20 g · kg-1 once a day at the 2nd day after the success of the model,and the normal group and diabetic group were given methylene chloride.Finally,after immunohistochemical staining for retina,TUNEL assay was used to evaluate the apoptosis of RGCs,while the expression of SIRTI,p38 MAPK and Caspase-3 protein was detected by Western blot.Results The apoptotic index of RGCs in the normal group,diabetic group and treatment group was (0.848+0.131)％,(19.038 + 1.327)％,(10.461 + 1.089)％ respectively at 8 weeks,and the difference among the three groups was statistically significant (F =670.497,P =0.000),while the differences between each two groups were also statistically significant (all P =0.000).Furthermore,when compared with the normal group (0.132 ± 0.043),the expression of SIRT1 protein in the diabetic group (0.060 ± 0.028) and the treatment group (0.073 ± 0.026) was significantly decreased,and the overall difference among the three groups was statistically significant (F =1 310.663,P =0.000),while the differences between each two groups were also statistically significant (all P =0.000).The expression levels of p38 MAPK and Caspase-3 were increased in diabetic group (1.121 ± 0.082,0.266 ± 0.005) and treatment group (0.574 ± 0.012,0.190 ±0.060) respectively,and the overall difference and pairwise comparison in the three groups approached statistically significance (all P =0.000,0.000).Conelusion Up-regulation of SIRT1,can inhibit the apoptosis of RGCs,and protect RGCs against apoptosis in rat model of diabetic retinopathy,which may be correlated with the downregulation of p38 MAPK signal pathway.
ABSTRACT
Objective:To investigate the regulation effect of endogenous nicotinamide phosphoribosyl transferase (Nampt) on the Vimentin expression of glomerular cells in high concentration glucose,and to clarify the mechanism of formation of diabetic kidney inflammation fibrosis.Methods:The C57/BL6 diabetic mice were selected and the kidney tissues were collected,and the wild C57/L86 mice were used as control group;the pathological section and tissue fluorescence staining were performed.The expression and location of endogenous Nampt and Vimentin in the glomerular cells were detected by immuno-focused technology.The HBZY-1 cells were randomly divided into 4 groups:low concentration of glucose (LG,0.56 mmol · L-1) control group,high concentration glucose (HG,200 mmol · L-1) group,HG +-FK866 group and HG+nicotinamide mononucleotide (NMN) group.In HG group,the cells were treated with FK866 (10 μmol · L-1) and NMN (1 mmol · L-1) for 24 h after cultured with HG for 5 d.The expression levels of Nampt,Vimentin,nuclear factor-kappa B p65 (NF-κBp65) and sirtuin type 1 (Sirt1) were detected by immunofluorescence and Western blotting methods.The expression levels of Nampt and Vimentin were detected by RT-PCR and Western blotting methods.Results:The shape and size of glomerulus had obvious atrophy of the mice in severe diabetic group compared with normal C57/BL6 mice group.The expression level of Vimentin in glomerular cells was increased with the increasing of endogenous Nampt (P＜0.01).When the HBZY-1 cells were cultured in HG condition,the exprssion levels of Nampt,Vimentin and NF-kB p65 were obviously increased while the Sirt1 expression levels was significantly decreased compared with control group (P＜ 0.01).The expression levels of Nampt,Vimentin and NF-κB p65 in glomerular cells in HG+FK866 HG+ NMN groups were singnificartyly decreased compared with control group (P＜0.01).Conclusion:The endogenous Nampt over-expression in glomerular cells can enhance the expression of Vimentin under high concentration of glucose stress through NF-κBp65 and Sirt1 signal pathway.
ABSTRACT
Objective:To investigate the regulation effect of endogenous nicotinamide phosphoribosyl transferase (Nampt) on the Vimentin expression of glomerular cells in high concentration glucose,and to clarify the mechanism of formation of diabetic kidney inflammation fibrosis.Methods:The C57/BL6 diabetic mice were selected and the kidney tissues were collected,and the wild C57/L86 mice were used as control group;the pathological section and tissue fluorescence staining were performed.The expression and location of endogenous Nampt and Vimentin in the glomerular cells were detected by immuno-focused technology.The HBZY-1 cells were randomly divided into 4 groups:low concentration of glucose (LG,0.56 mmol · L-1) control group,high concentration glucose (HG,200 mmol · L-1) group,HG +-FK866 group and HG+nicotinamide mononucleotide (NMN) group.In HG group,the cells were treated with FK866 (10 μmol · L-1) and NMN (1 mmol · L-1) for 24 h after cultured with HG for 5 d.The expression levels of Nampt,Vimentin,nuclear factor-kappa B p65 (NF-κBp65) and sirtuin type 1 (Sirt1) were detected by immunofluorescence and Western blotting methods.The expression levels of Nampt and Vimentin were detected by RT-PCR and Western blotting methods.Results:The shape and size of glomerulus had obvious atrophy of the mice in severe diabetic group compared with normal C57/BL6 mice group.The expression level of Vimentin in glomerular cells was increased with the increasing of endogenous Nampt (P＜0.01).When the HBZY-1 cells were cultured in HG condition,the exprssion levels of Nampt,Vimentin and NF-kB p65 were obviously increased while the Sirt1 expression levels was significantly decreased compared with control group (P＜ 0.01).The expression levels of Nampt,Vimentin and NF-κB p65 in glomerular cells in HG+FK866 HG+ NMN groups were singnificartyly decreased compared with control group (P＜0.01).Conclusion:The endogenous Nampt over-expression in glomerular cells can enhance the expression of Vimentin under high concentration of glucose stress through NF-κBp65 and Sirt1 signal pathway.
ABSTRACT
Objective To investigate the effect of silment information regulator factor related enzymes 1 (SIRT1) on the apoptosis of retinal ganglion cells (RGCs) in rats with diabetic retinopathy and its downstream molecular mechanisms.Methods Together 60 healthy male Sprague-Dawley rats were collected and randomly divided into normal group,diabetic group,SIRTI activator-resveratrol treatment group (treatment group),and diabetic rat model was induced by intraperitoneal injection of streptozotocin at 60 mg · kg-1 in the latter two group rats,while the normal group was injected with sodium citrate buffer at 60 mg · kg-1.Then,after 72 h,rats with blood glucose ＞ 16.7 mmol · L-1 were designated as diabetic rats by blood glucose test.Then each rat in the treatment group was treated with SIRT1 activator-resveratrol at 20 g · kg-1 once a day at the 2nd day after the success of the model,and the normal group and diabetic group were given methylene chloride.Finally,after immunohistochemical staining for retina,TUNEL assay was used to evaluate the apoptosis of RGCs,while the expression of SIRTI,p38 MAPK and Caspase-3 protein was detected by Western blot.Results The apoptotic index of RGCs in the normal group,diabetic group and treatment group was (0.848+0.131)％,(19.038 + 1.327)％,(10.461 + 1.089)％ respectively at 8 weeks,and the difference among the three groups was statistically significant (F =670.497,P =0.000),while the differences between each two groups were also statistically significant (all P =0.000).Furthermore,when compared with the normal group (0.132 ± 0.043),the expression of SIRT1 protein in the diabetic group (0.060 ± 0.028) and the treatment group (0.073 ± 0.026) was significantly decreased,and the overall difference among the three groups was statistically significant (F =1 310.663,P =0.000),while the differences between each two groups were also statistically significant (all P =0.000).The expression levels of p38 MAPK and Caspase-3 were increased in diabetic group (1.121 ± 0.082,0.266 ± 0.005) and treatment group (0.574 ± 0.012,0.190 ±0.060) respectively,and the overall difference and pairwise comparison in the three groups approached statistically significance (all P =0.000,0.000).Conelusion Up-regulation of SIRT1,can inhibit the apoptosis of RGCs,and protect RGCs against apoptosis in rat model of diabetic retinopathy,which may be correlated with the downregulation of p38 MAPK signal pathway.