依赖性膜磷脂结合蛋白AnnexinⅡ对大鼠脊髓横断损伤的修复作用

EFFECT OF ANNEXINⅡ ON THE REPAIR OF SPINAL CORD INJURY OF THE RATS

目的在体内实验中观察钙依赖性膜磷脂结合蛋白AnnexinⅡ对大鼠脊髓损伤以及神经干细胞移植的作用。方法在成年大鼠全横断脊髓损伤的局部微量注射AnnexinⅡ,观察其对损伤的脊髓神经细胞存活、神经纤维生长和损伤后的功能恢复的影响,以及对联合移植的胚胎神经干细胞移植后存活和迁移的影响。结果在动物脊髓横断损伤6周,神经干细胞移植4周后,损伤局部微量注射AnnexinⅡ+NSC移植组实验动物的运动评分结果较空白对照组和单独进行NSC移植组都有明显增高(P<0.01),脊髓损伤处的空洞面积也较上述两组显著减小(P<0.01);注射AnnexinⅡ+NSC组损伤节段以上荧光金标记神经细胞数目较空白对照组明显增多(P<0.01)。结论AnnexinⅡ蛋白可能具有减小局部损伤空洞面积,保护损伤的神经元和神经纤维并防止其走向变性和死亡的效应,并对神经干细胞的移植效应有一定的促进和协同作用,使脊髓损伤大鼠的功能得到一定程度的恢复。

Objective In order to make further investigation of the functional meaning of Ca^＋2 -dependent phospholipids binding protein Annexin Ⅱ , we tested the effects of Annexin Ⅱ combined with embryonic neural stem cells （NSCs） transplantion on the repair of spinal cord injury （SCI）. Methods The spinal cord of the adult rats was transected completely between T9-T10 Annexin Ⅱ and NSCs were injected at the transected site. The lesion area of the spinal cord, growth of axon, and survival number and migration of the transplanted NSCs were measured. The survival number was shown by prelabeling the NSCs with Hoechest 33342 and the growth of axon traversing the transected area was shown by fluorogold （FG） retrograde tracing. The Annexin Ⅱ injection ＋ NSCs implantation groups were compared with groups that respectively received 1. NSCs implantation alone ; 2. shamoperation ＋ NSCs implantation and 3. Vehicle injection of culture medium. Results Our results demonstrated that Annexin Ⅱ treatment in vivo could significantly reduce the lesion area （P 〈 0.01 ）, increase the number of FG retrogradely-labeled neurons rostral to the injury （ P 〈 0.01 ）, and improve the inclined plane and BBB locomotor rating scales （ P 〈 0.01 ） at 6 weeks after SCI. Conclusion These results suggest that annexins proteins may play an role of protection. Intraspinal injection of Annexin Ⅱ may reduce spinal cord secondary injury, then promote axonal growth, improve functional recovery after a transection of the spinal cord in adult rats and may have beneficial effects on implanted neural stem cells when treated synchronously.