Effect Of Recombinant Adenovirus Angiopoietin-1 On The Renal Angiogenesis In Diabetic Rats

Background and objective:The development of diabetic nephropathy(DN) was mainly attributed to abnormality of renal microvascure structure and function, including angiogenesis.These changes are usually thought to relate to the disorder of angiogenetic regulatory factors.It was reported that antagonism of vascular endothelial growth factor(VEGF) could ameliorate the renal lesions in diabetic rats, but this intervention is not contribute to the treatment of macrovascular complications of diabetes mellitus(DM).Angiopoietin-1(Ang-1) is a recently discovered vascular-specific growth factor which has promoted vascular maturation and stabilization,and reduce the blood leakage and cell apoptosis.The aim of this study was to investigate the effect of administration of recombinant advenorivus Ang-1(Ad-Ang-1) on renal angiogenetic markers in diabetic rats.We hope that the result will provide a good idea for the treatment of macro-and microvascular complications in DM.Methods:Ad-Ang-1 was first constructed and identified,SD rat model of diabetic nephropathy was induced by one intraperitoneal injection of streptozotocin(STZ). The subjects were divided into four groups:the diabetes group(n=24),the Ang-1 treatment group(diabetic rat was only administrated with Ad-ang-1 at 8 week,n=24], the vector group(diabetic rat was only administrated with adenovirus vector at 8 week, n=24),and the normal control.At different time points,urinary protein,serum creatinine,renal pathologic changes were respectively observed,the expression of Ang-2 mRNA in renal tissue was analyzed by RT-PCR,the levels of angiopoietin-2(Ang-2),thrombomodulin-1(TM-1),and Ki-67 in renal tissue were detected by immunofluorescence in four groups.Result:①The levels of urinary protein,and serum creatinine in the three diabetic model groups were significantly increased as compared with the normal control group(P＜0.01),but urinary protein at 28 weeks was significantly lower in Ang-1 treatment group than in other two diabetic groups(P＜0.01).②Ang-2 was not detected without experimental period in normal control group.The expression of Ang-2 mRNA and protein in the three model groups were significantly up-regulated from 12 to 28 weeks,particularly in the Ang-1 treatment group(vs.the other two diabetic model groups,P＜0.05-0.01),with peak level at 20 week.Ang-2 fluorescence was mainly found in glomeruli and tubulointerstitium.③TM-1 fluorescence was found especially in glomeruli in four groups,and was obviously stronger in three diabetic model groups than in the normal control group(P＜0.01), with peak level at 20 weeks.④Ki-67 fluorescence was not found in the normal control group,but was mainly found in glomeruli of the three diabetic model goups with peak level at 20 week,and increased in Ang-1 treatment group as compared with the other two diabetic groups(P＜0.01).⑤Urinary protein excretion was correlated with Ang-2(r=-0.601,P＜0.05) or TM-1(r=0.704,P=0.000).Conclusion:Administration of Ad-Ang-1 has some protective effect on angiogenesis for diabetic kidney.