Distribution of the transplanted cells in twitcher mice brain. (A) The enhanced green fluorescent protein (eGFP)-positive cells were located along the injection tract: (a, d) eGFP-positive cells (green), (b, e) nuclei were stained with 6-diamidino-2-phenylindole (DAPI) (blue), (c, f) merge. (B) Real-time reverse transcription-polymerase chain reaction (RT-PCR) results of eGFP at different time points after injection. Compared with day 1 after injection, the expression level of eGFP significantly decreased at days 10 and 20 (0.09 ± 0.05 and 0.06 ± 0.04 versus 0.96 ± 0.22, both P <0.01). (C) Dir-labeled cells in twitcher mice brains were detected by in-Vivo Multispectral Imaging System. The strengths of fluorescent signal at days 1, 10, and 20 after injection were 25,522 ± 6,287, 11,372 ± 2,162, and 7,077 ± 1,022, and the differences were statistically significant (all P <0.01).