嗅鞘细胞移植对大鼠脊髓半横断损伤后轴突再生及后肢功能恢复的作用

为了对嗅鞘细胞移植治疗大鼠脊髓损伤(spinal cord injury, SCI)后轴突再生及后肢功能恢复进行综合性的评价,本实验采用22只雌性成年SD大鼠,并随机分成A、B、C、D 4组。其中A、B、D组行左侧T11 ～T12节段脊髓半横断手术,然后A组移植嗅鞘细胞(olfactory ensheathing cells,OECs)悬液;B组移植DMEM/F12培养液;D组移植核荧光试剂(Hoechst33342)标记的嗅鞘细胞,用于鉴定嗅鞘细胞在体内的存活情况;C组作为正常对照组。术后6周内,对大鼠进行BBB评分、IP斜板试验并观察皮质体感诱发电位(cortical somatosensory evoked potential, CSEP)、运动诱发电位(motor evoked potential, MEP)的潜伏期。将辣根过氧化物酶(HRP)注射到横断面尾段脊髓,逆行追踪观察横断面头段脊髓及对侧中脑红核内HRP逆标细胞数,并观察左侧后肢小腿三头肌肌细胞横截面积及直径的变化。结果显示:(1)移植后的OECs数量未见明显减少,细胞核形态较好,细胞未向头、尾侧迁移;(2)移植3周后BBB评分及IP斜板,试验A、B组较C组明显低(P<0.05),但A组明显高于B组(P<0.05);(3)A、B组的CSEP及MEP潜伏期较C组明显延长(P<0.05),但A组要比B组明显缩短(P<0.05);(4)HRP逆行追踪观察到对侧中脑红核大细胞区及脊髓T9 ～T11节段逆标细胞的数量,A组明显多于B组,但A、B组均少于C组;(5)左侧后肢小腿三头肌肌细胞的横截面积及直径,A、B组均较C组减少,但A组减小的幅度明显小于B组。以上结果表明OECs移植能促进半横断脊髓轴突的再生及后肢功能的恢复。

Effects of transplanted olfactory ensheathing cells on axon regeneration and hindlimb functional recovery after spinal cord hemisection in the rat

To investigate the effects of transplanted olfactory ensheathing cells(OECs) on axon regeneration and hindlimb functional recovery after spinal cord hemisection in the rat,a total of 22 female adult healthy Sprague-Dawley rats were randomly divided into 4 groups(groups A,B,C and D).The spinal cord hemisection injury models of groups A,B and D were made by cutting the left side spinal cord at T11-T12.Group A was transplanted with suspension of olfactory ensheathing cells(OECs),group B was transplanted with DMEM/F12 culture fluid,meanwhile group D was transplanted with suspension of OECs which were labeled with nucleo-fluorescent reagent(Hoechst33342),which was used to detect the survival of OECs in vivo.Group C was normal control group.During 6 weeks after operation,Basso-Beattie-Bresnahan(BBB) locomotor rating scale and Inclined Plan(IP) experiment were tested;the latencys of cortical somatosensory evoked potential(CSEP)and motor evoked potential(MEP)were detected.HRP was injected into the caudal segment of transected spinal cord to observe the number of HRP-labeled cells in red nucleus in contralateral side and the rostral end of transected spinal cord in ipsilateral side;the changes of cross section area and diameter of muscular fibers of left triceps surae were measured.The results showed that:(1) The number of transplanted OECs was not reduced obviously,and the morphous of nuclei of those cells did not change.OECs did not move toward rostral and caudal ends of injected site;(2)The BBB locomotor rating scale and the score of IP experiment of group A were significantly increased than that of group B on the 3rd week after operation(P<0.05)although group A and B was significantly lower than group C(P<0.05);(3) The latency of CSEP and MEP of group A was significantly shorter than that of group B(P<0.05),but both of them were still longer than that of group C(P<0.05);(4) The results of HRP-retrograde tracing showed that HRP-labeled cells of group A in red nucleus in contralateral side and the rostral end of transected spinal cord in ipsilateral side were more than those of group B,though group A and B were less than group C;(5) The cross section area and diameter of skeletal muscle fibers in left triceps surae of group A and B were decreased than that of normal C group,but the decreasing extent of group A is less than that of group B.All of the results indicate that axon regeneration and the hindlimb nctional recovery were promoted by OECs transplantation in rats with hemisection of spinal cord injury.