Bcl-2 overexpression in cultured and transplanted cells. (A) Significantly high expression of Bcl-2 was observed in cell cultures overexpressing the Bcl-2 gene 24 hours after transfection. In contrast, a weak expression of Bcl-2 was detected in vector-NESC. (B) In animal studies, 1 week after transplantation, a higher level Bcl-2 expression was seen in the transplanted colonic tissues from the Bcl-2 group compared with that from the control group. The Bcl-2 level remained high for up to 8 weeks after transplantation. (C), (D) Bar graphs showing the Bcl-2 levels in cultures and in cell grafted colons. At different days after transplantation, significantly higher Bcl-2 expression was seen in the colons of rats receiving Bcl-2-NESC than those receiving vector-NESC. *Significant difference compared with vector-NESC or control group (P < 0.05, n = 6 for cell culture experiments and n = 6 for animal studies). NESC, neuroepithelial stem cell.