An experimental study on protective effect of extracellulsr ATP to motorneurons on spinal cord after brachial plexus avulsion

Abstract

Objective To investigate the protective effect of extracellular ATP on motoneurons of spinal anterior horn from spinal root avulsion induced cell injurey. Methods Thirty-six Wister rats were randomized into 2 groups: single root avulsion and root avulsion with ATP. The left C5-C8 nerve roots were avulsed, the experiment group was gioven extracellular ATP (2 mg/kg) 0.4 ml by intraperitoneal injection and control group physiological saline water was gioven 0.4ml as the same method, all one time daily, contin-ue injection ATP or saline water 2 weeks. At 2,4 and 6 week postoperatively, C5-C8 spinal cord was har-vested after the rats were executed. The change of nitric oxide synthase (NOS) and neurofilament protein (NF-200) were observed after histochemistrical examination. Results At 2、4 and 6 week postoperatively, the survival of motorneurons in the spinal anterior was 80.48%, 73.55% and 53.43% in experiment group, was 68.90%、63.58% and 37.72% in control group;compare experiment group with control group, the le-don-induced motomeurons death in the spinal anterior bern was decreased by 11.58%、9.78% and 15.71% respectively (P < 0.01) ; the activity changes of NOS expression rate was 17.85% ,40.20% and 18.03% in experiment group, was 25.53%,53.88% and 25.58% in control group, compare experiment group with con-trol group, the activity changes of NOS expression rate was decreased by 7.68% (P < 0.01), 13.68% and 7.55% (P < 0.05) respectively. The motoneurons expressed NF-200 in the experiment group was larger than the control group, there was significant difference was found between the control group and the experiment group. Conclusion ATP might play certain protective role in survival of motoneurous after spinal root avulsion. Key words: Brachial plexus; Avulsion; Spinal cord; Motoneuron; Adenosine triphospbete