RESUMEN
<p><b>OBJECTIVE</b>To investigate the expression of alpha smooth muscle actin (alphaSMA), a marker of myofibroblast in kidney of diabetic rats and its role in pathogenesis of diabetic nephropathy.</p><p><b>METHODS</b>Diabetic disease model was made on 24 Sprague-Dauley (SD) rats by an single intraperitoneal injection of streptozotocin (70 mg/kg) and 24 health SD rats served as controls. Six diabetic rats and six control rats were sacrificed at 1, 2, 4, 8 weeks after injection of streptozotocin. At each time-point, the renal morphological changes were examined by histopathology. alpha SMA and collagen-IV (C-IV) expressions were studied by immunohistochemistry (SABC). The content of alpha SMA in renal cortex was detected by enzyme-linked immunosorbent assay(ELISA).</p><p><b>RESULTS</b>At all time-points, renal content of alpha SMA increased in diabetic rats. Compared with controls, diabetic rats had a steady increased accumulation of C-IV. Expression of C-IV was positively correlated with that of alpha SMA.</p><p><b>CONCLUSION</b>At early stage of diabetes,increased alpha SMA in kidney suggests the formation of myofibroblast, which may be involved in accumulation of C-IV and contributed to diabetic nephropathy.</p>