Mesenchymal stem cells infusion prevents acute cellular rejection in rat kidney transplantation

Mesenchymal stem cells (MSC) are multipotent cells that differentiate into various mature cell lineages. MSC show immunomodulatory effects by inhibiting T-cell proliferation. We evaluated the effect of the infusion of MSC in rats experimental kidney transplantation. Sprague-Dawley transgenic rats (SD) able to express the green fluorescent protein (EGFP) were used as MSC donors. Syngeneic (Lewis to Lewis, n = 10) and allogeneic (Fischer to Lewis, n = 10) kidney transplantations were performed after bilateral nephrectomy. Five transplanted rats who received syngeneic grafts, were treated with 3 x 10(6) MSC (Gr B), while the other 5 did not received MSC (Gr A). Five rats with allogenic grafts received 3 x 10(6) MSC (Gr C) and another 5 did not receive MSC (Gr D). The MSC were infused directly into the renal artery of the graft. No immunosuppressive therapy was provided. The animals were killed after 7 days. Biochemical analysis for renal function, histological (Banff criteria) and immunohistological analysis (ED1+ and CD8+) were performed on treated animals. MSC improved kidney function in Gr B and D vs Gr A and C. The tubular damage appeared to be less severe among Gr B and Gr D with respect to Gr A and C (P < .01). Vasculitis was more accentuated in Gr A and C (P < .01). MSCs reduced the inflammatory infiltrate; in Gr B and D, the number of ED1+ cells was lower than in Gr A and C (P < .005), which was also observed for CD8+ cells (P < .05). Our study demonstrated that the infusion of MSC attenuated histological damage from acute rejection by reducing the cellular infiltration.