The Effect Of Intermedin On Interstitial Angiogenesis Of UUO Rats

Objective:To observe the effect of intermedin on interstitial angiogenesis in rats with unilateral ureteral obstruction(UUO) model for renal interstitial fibrosis.Methods:(1)modeling and experimenting in groups:Seventy-two male Wistar rats were randomly divided into the sham-operation group(n=24 with left ureter dissection),the UUO( n=24)and the IMD group( n=24).The UUO and IMD group underwent ligation of the left ureter.At the day 7、14、21 and 28 after operation,randomly 6 rats from each group were blooded by abdominal arotic and obstractive kidneys were taken out.(2)To detect serum BUN,Scr and Cys C content.(3)To assess the extent of damage in renal interstitial by HE and PAS staining.(4)Immunohistochemical method was used to detect platelet endothelial cell adhesion molecule(CD31or PECAM-1), CD34, aminopeptidase P( APP or JG-l2), vascular endothelial growth factor(VEGF), VEGF receptor-2(VEGFR2) and vascular endothelial cadherin(VE-cadherin) expression.(5)Real Time-PCR was used to detect VEGF, VEGFR2 and VE-cadherin m RNA expression in renal tissue.Results:(1)blood biochemical changes: Compared with Sham group, UUO group at different time points serum BUN, Scr and Cys C were increased(P <0.05), and peaked at 21 d,after lowering.Compared with UUO group, IMD serum BUN, Scr and Cys C were lower(P <0.05).(2)renal histological changes:Optical microscope microscope revealed:Kidney tissue structure is clear, glomerular structure normal, renal tubular epithelial cells complete, arranged in good order in Sham group.After 7d postoperative inflammatory cells infiltrate, while some tubules are degenerate in UUO group.After 14 d, inflammatory cells infiltrate and proliferate significantly, fibroblast proliferate, some renal tubular structure is incomplete,some kidney tubules dilatate in cryptomere,and cortical thins in UUO group.After 21 d,some renal tubular structure disappeare, inflammatory cells infiltrate and proliferate, and interstitial fibrosis in UUO group.After 28 d, inflammatory cells infiltration decrease, the number of renal tubular dilation appear, some tubular atrophy and disappeared, and interstitial fibrosis is obvious in UUO group. PAS staining diffuse tubular basement membrane thicken and shrinkage increase.Compared with UUO group, IMD group inflammatory cells infiltrate, tubular injury and fibrosis are not so fierce.(3)Tubulointerstitial injury score: Compared with Sham group, the extent of damage in rats at different time points UUO group were higher(P <0.05).Compared with UUO group, the extent of damage IMD group at 21 d, 28 d significantly reduced(P <0.05).(4)changes in markers of renal microvascular: Compared with Sham group, UUO group at different time points CD31, CD34, JG-12 expression was decreased(P <0.05).Compared with UUO group, IMD group, three markers were positively increased(P <0.05).(5)VEGF, VEGFR-2 m RNA and protein expression:Compared with Sham group, UUO group at different time points VEGF, VEGFR2 m RNA and protein expression levels decreased(P<0.05). Compared with UUO group, IMD group both m RNA and protein expression levels increased(P <0.05).(6)VE-cadherin m RNA and protein expression: Compared with Sham group, UUO group VE-cadherin m RNA gradually increased by less than Sham group to transcend the Sham group, and peaked at 21 d, after lower and at different time points VE-cadherin protein levels decreased(P <0.05). Compared with UUO group, IMD group VE-cadherin m RNA expression level there is a growing trend and VE-cadherin protein expression levels increased(P <0.05)Conclusions:IMD can protect vascular in the kidney from damage, increase microvessel density(MVD). Through increasing VEGF-VEGFR2 pathway,it promotes angiogenesis in injured renal, and increases its pathways interaction with the VE-cadherin to maintain the integrity of the vessels,which improves renal function, delay renal fibrosis.