Effects of neural stem cells transplantation on apoptosis-related genes expression in the motor cortex of rats subjected to spinal cord transection / 中国组织工程研究

ABSTRACT

BACKGROUND: Many studies showed that neural stem cells (NSC) transplantation can promote functional improvements in rats subjected to spinal cord injury. However, the underlying molecular mechanisms remain poorly understood.OBJECTIVE: To observe the effects of NSC transplantation on expressions of Bax, Bcl-2 and Caspase-3 in the motor cortex in rats subjected to spinal cord transection.DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed at Institute of Neuroscience,Kunming Medical College from July 2007 to December 2008.MATERIALS: Five green fluorescent protein transgenic mice with 14-15 embryonic days were prepared for NSC. Additionally 88 adult female Sprague-Dawley (SD) rats were randomly divided into sham operation group (n=8), model group (n=40) and NSC transplantation group (n=40).METHODS: Model of spinal cord transection was established by cut transversely Sprague-Dawley (SD) rats T_9 segment. Rats in the sham operation group were subjected to laminectomy at T_8, without spinal cord injury. After the spinal cord was exposed at the lesion site, a small piece of 2 mm~3 gel foam soaked with 3×10~5 NSC were implanted into the gap to fill the lesion site of the T_9 level in rats of the NSC transplantation group. The measurements of relative indexes were performed at the days 3, 7,14, 21 and 28 after transplantation.MAIN OUTCOME MEASURES: Changes of Bax, Bcl-2 and Caspase-3 expressions were detected by RT-PCR.RESULTS: Compared to the sham operation group, the Bax expression in the model group had no significant difference (P >0.05), the expression of Bcl-2 was decreased obviously at days 14 and 28 after operation (P < 0.05), while a significant increase on the expression of Caspase-3 at day 3 (P < 0.05). Compared to the model group, the expression of Bax was dramatically decreased in the NSC transplantation group at day 3 (P < 0.05), with a notably increased Bcl-2 expression at days 14 and 21 after transplantation (P < 0.05), but the expression of Caspase-3 presented a significant decrease at days 3 and 7 after transplantation (P < 0.05).CONCLUSION: NSC transplantation probably regulates the expression of apoptosis genes (Bax, Bcl-2 and Caspase-3 mRNA) to promote neurological function recovery in rats subjected to cord transection.