The role of cell proliferation and apoptosis in renal tubulointerstitial fibrosis caused by unilateral ureteral obstruction
HUANG Hongling, ZHANG Guoqiang,YE Rengao, et al. Department of Nephrology, Key Clinical Kidney Research Institnte of Minitry of Health, First Affiliated Hospital, Sun Yat-sen University of Medical Sciences, Guangzhou 510089, China
Objective To Further clarify the role of cell proliferation and apoptosis in the patho genesis of renal tubulinterstitial fibrosis. Methods The time course of the fibrotic process in rats with unilateral ureteral obstruction(UUO) was examined and the expressions of proliferative cell muclear antigen (PCNA), α-smooth muscle actin(α-SMA) and apoptosis in renal tubulointerstitium were observed. Results Through day 3 to day 11 an increase in apoptotic cells was defected by in situ end-labeling of cleaved DNA in foe obstructed kidney. Most of the apoptotic cells were detected individually in tubular epithelial cells, but apoptotic nuclei were also found in the interstitial area. The expression of PCNA in both tubular epithelial and interstitial cells peaked at day 3, and then declined. Though there was a transient increase in both proliferative and apoptotic activity of tubulointerstitial cells, the proliferation/apoptosis index of tubular epithelial cells finally decreased to a level lower than normal, while the index of interstitial cells sustained to a level higher than normal. These changes were consistent with the sustained to a level higher than normal. These changes were consistent with the expression of α-SMA, and with the persistent increase of the relative volume of the conical interstitium (Vv). Conclusions Cell proliferation and apoptosis participate in renal interstitial fibrogenesis in UUO models. They are two important parameters in this process.