Expression of surfactant protein A in the rat kidney with acute pyelonephritis / 中华肾脏病杂志

ABSTRACT

Objective To characterize the expression of surfactant protein A (SP-A) in normal and acute pyelonephritic rat kidneys and to study the correlation of infection and inflammation with SP-A expression. Methods Twenty-one rats were randomly assigned into three groups control, sham operation and pyelonephritic group. HE staining was used to determine tubulointerstitial inflammation. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting were used to determine the mRNA expression and protein level of SP-A. Immunohistochemical staining was used to label the localization and intensity of SP-A expression in kidney tissue. The correlation between intensity of SP-A expression and interstitial inflammation was also evaluated. Results In pyelonephritic group, tubulointerstitial inflammation was more prominent than that in control and sham groups (54.3?11.5,6.4?1.4, 8.6?1.9,respectively). RT-PCR and Western blotting revealed that SP-A expression was up-regulated in pyelonephritic group (in mRNA level 2.2+0.58, 0.9?0.25, 1.1? 0.30; in protein level 0.45?0.09, 0.24?0.05, 0.26?0.05, respectively). Immunohistochemical staining demonstrated that SP-A expression was mainly localized on epithelial cells in outer medullary and collecting tubules in normal group and sham group, but strong staining extended to collecting tubules in pyelonephritic group. The tubulointerstitial inflammation score was positively correlated with the intensity of SP-A expression (r=0.67,P