Tubular cell apoptosis and proliferation in the early phase of renal damage in uninephrectomized SHR.

In the present study, we measured tubular cell apoptosis and proliferation and Bcl-2 expression during the early phase (3 months) of the process of renal fibrosis in the experimental model of uninephrectomized spontaneously hypertensive rats (SHR). Tubulointerstitial fibrosis was evaluated by automated quantitative morphometry using selective staining of the extracellular matrix with sirius red. Apoptosis was quantified by both in situ dUTP biotin nick end-labeling method (TUNEL) and by propidium iodide staining. Proliferation rate was measured by counting cells expressing the proliferating cell nuclear antigen. Bcl-2 expression was assessed by immunohistochemistry. Tubulointerstitial fibrosis increased progressively during the 3 months of follow-up. Proliferation and apoptosis rates in tubular cells increased from the first to the second month after UNX. In the third month after UNX, the proliferating tubular cell number continued to increase, whereas the apoptotic cell number was maintained, coinciding with an increase in the expression of Bcl-2. Our observations demonstrate a different profile of tubular cell proliferation and apoptosis during the genesis of early tubulointerstitial damage in UNX-SHR.