Expression And Significance Of Nitric Oxide Synthase In Ureteropelvic Junction Obstruction

Objcetive The aim of the present study was to research the expression and distribution of three kinds of nitric oxide synthase (nNOS, eNOS and iNOS) in normal ureteropelvic junction (UPJ) and ureteropelvic junction obstruction (UPJO) , and to explore their roles in the pathogenetic mechanism of ureteropelvic junction obstruction.Methods Immunohistochemical staining (SABC method) was performed to detect the expression of three kinds of NOS in the specimens of 36 UPJO tissues and of 20 normal control UPJ tissues obtained from renal neoplasm. Area, MD and IOD of the NOS expression were determined by image analysis technique and meanwhile quantitative analysis was made. Correlations between the NOS expression and age / hydronephrosis degree were investigated.Results ① Immunoreactivity to nNOS was predominantly seen in the urothelium and the smooth muscle cell. Area, MD and IOD of the nNOS expression was significantly reduced in the urothelium of UPJO compared to the normal UPJ , respectively (P<0.001, P<0.001, P<0.001). There was a marked reduction of Area, MD and IOD of the nNOS expression in the muscle layers of UPJO, respectively(P<0.001,P<0.001, and P<0.001). ② The eNOS reaction production was located in vascular endothelial cells. The level of Area, MD and IOD of the eNOS expression in UPJO was much lower than those in the normal group, respectively(P=0.015, P=0.022, P=0.003). ③ The expression of iNOS was mainly present in the smooth muscle cell. iNOS exhibited a similar expression pattern in the two groups . Thedifferences of Area^ MD and IOD were not statistically significant CP =0. 149, P=0. 186, P=0. 065 , respectively) . ? The expressions of nNOS^ eNOS and iNOS in normal group were independent of age (P=0. 629, P=0. 372, P=0. 583) . (§) In UPJO, the expressions of nNOS and eNOS were not related to age (.P =0.122, P =0.180) . A negative correlation was found between the nNOS expression and the hydronephrosis degree ( r =-0. 650, P <0. 001). There was not significant correlation between the eNOS expression and the hydronephrosis degree (P =0.119) .Conclusions K The distribution of nNOS in UPJ is general. The decreased expression of nNOS may play an important role in the pathogenesis of UPJO. 2, The eNOS positive substance is only distributed in vascular endothelial cells. We presume that eNOS mainly regulates the bloodstream of UPJ and is partly involved in the pathogenesis of UPJO. 3> The difference of the iNOS expression in two groups is not statistically significant, and iNOSmay not participate in pathogenic mechanism of UPJO.