Bcl-xL expression improves the therapeutic effect of human umbilical cord stem cell transplantation on articular cartilage injury in rabbit.

Background: To investigate the therapeutic effect of transplantation of B-cell lymphoma-extra large (Bcl-xL) gene modified human umbilical cord blood stem cells (HUCSCs) on rabbit articular cartilage injury.

Materials And Methods: HUCSCs were isolated and identified. Lentiviral encoding Bcl-xL was applied to modify HUCSCs. The effects of Bcl-xL overexpression on apoptosis and related gene expression after differentiation induction of HUCSCs were detected. Additionally, the efficiency of transplantation of Bcl-xL gene modified HUCSCs on articular cartilage injury were evaluated.

Results: HUCSCs could differentiate into chondrocytes after induction. Compared with control group, the apoptosis after induction was significantly elevated, but reduced by Bcl-xL gene overexpression. The differentiation of HUCSCs into chondrocytes was displayed by expression of type II collagen (CII), but accompanying with expression of caspase-3 and matrix metalloproteinase-3 (MMP-3). By contrast, Bcl-xL gene overexpression reduced caspase-3 and MMP-3 expression, but further increased CII expression. Pathological staining showed that Bcl-xL gene modified HUCSCs could obviously repair cartilage injury. Compared with sham control group, the expression of caspase-3 and MMP-3 in model group was significantly up-regulated, while the expression of CII was significantly down-regulated. Transplantation of HUCSCs could ameliorate the injury, while Bcl-xL modification could improve the therapeutic effect of transplantation of HUCSCs. Moreover, Bcl-xL modification could further decrease cartilage injury-induced expression of caspase-3 and MMP-3, and improve the expression of CII compared with transplantation of normal HUCSCs.

Conclusions: Bcl-xL gene modification decreases cell differentiation-induced apoptosis and improves the efficiency of HUCSCs transplantation in the repairing of cartilage injury.