RESUMEN
<p><b>OBJECTIVE</b>To investigate the effect of bone mesenchymal stem cell (BMSC) transplantation on repair of glomerular podocytes and on the Nephrin expression in rats with puromycin aminonucleoside (PAN) -induced nephrosis.</p><p><b>METHODS</b>Forty-five Sprague-Dawley rats were randomly divided into three groups (n=15 each): a nephrosis model group that received a single intraperitoneal injection of PAN (0.15 mg/g); a BMSC transplantation group that received a single intraperitoneal injection of PAN (0.15 mg/g) followed by BMSC transfusion; a control group that received a single intraperitoneal injection of normal saline. Ten days after injection, the rats were sacrificed. The 24 hrs urinary protein content and serum albumin and cholesterol levels were measured 24 hrs before sacrifice. Changes of glomerular podocytes were observed under an electron microscope. Brdu labeled positive cells in kidneys were measured by immunohistochemical technology. RT-PCR and Western blot were used to assess the expression of mRNA and protein of Nephrin.</p><p><b>RESULTS</b>In the nephrosis model group, urinary protein and blood cholesterol contents increased, plasma albumin content decreased compared with those in the control group. Extensive fusion of podocyte foot processes was observed in the nephrosis model group. The BMSC transplantation group had decreased urinary protein and blood cholesterol contents and increased plasma albumin content compared with the nephrosis model group. Fusion of podocyte foot processes was also improved. Brdu labeled positive cells were seen in kidneys in the BMSC transplantation group, but not in the nephrosis model and the control groups. Nephrin mRNA and protein expression decreased significantly in the nephrosis model group compared with that in the control group. The BMSC transplantation group had increased Nephrin mRNA and protein expression compared with the nephrosis model group.</p><p><b>CONCLUSIONS</b>BMSCs can repair glomerular podocytes in PAN-induced nephrosis rats, and the changes of Nephrin expression may be involved in the process.</p>