RESUMEN
BACKGROUND:Stem cels can induce immune tolerance, prolong graft survival time and reduce rejection in organ transplantation, which have become a hot research. OBJECTIVE:To induce immune tolerance to alogenic kidney transplantation with amniotic fluid stem cels in recipient rats and to explore the mechanism underlying immune tolerance. METHODS: Amniotic fluid stem cels were isolated from Wistar rats. Two inbred male rat strains, Wistar rats and Sprague-Dawley rats, were selected as donors and recipients of kidney transplantation. The rat models of renal orthotopic transplantation were divided into the folowing four groups: a sham-operated group (n=10, Sprague-Dawley rats); an isograft group (n=10, Sprague-Dawley to Sprague-Dawley rats); a control group (n=10, Wistar to Sprague-Dawley rats, treated with 1 mL saline); and an experimental group (n=10, Wistar to Sprague-Dawley rats, treated with 1 mL of 3×106/L amniotic fluid stem cels). Serum levels of creatinine, urea nitrogen, interleukin-2, interferon-γ, parameters of oxidative stress were detected at 5 days after operation. Flow cytometry was employed to determine the percentage of CD4+ and CD8+ lymphocytes in the peripheral blood. Kidney transplants were observed pathologicaly. RESULTS AND CONCLUSION:Compared with the control group, the levels of creatinine, urea nitrogen, interleukin-2, interferon-γ, parameters of oxidative stress and proteinuria were lower in the experimental group (P < 0.05). Percentages of CD4+, CD8+ and CD4+/CD8+ ratio were also significantly lower in the experimental group than the control group. However, the rate of cretinemia clearance in the experimental group was significantly higher than that in the control group (P < 0.05). Furthermore, the degree of kidney injury in the experimental group was significantly lower than that in the control group. Our findings demonstrate that the amniotic fluid stem cel transplantation can induce immune tolerance, extenuate oxidative stress, attenuate pathological damage to the kidney transplant and preserve kidney function from acute rejection in rats undergoing kidney transplantation.