GDNF与甲泼尼龙对脊髓损伤后细胞内游离钙含量的影响

目的：比较胶质细胞源性神经营养因子（GDNF）与甲泼尼龙（MP）对脊髓损伤组织细胞内游离钙及水含量的影响。方法：SD大鼠分成对照组、GDNF组、MP一及GDNF＋MF组，改良Allen法撞击致伤脊髓T13节段，蛛网膜下腔给予GDNF 20μl,尾静脉给予MP 30mg/kg,不同时间取伤段脊髓以Fura-2法测定细胞内钙[Ca^2 ]i及组织中水含量。结果：治疗组[Ca^2 ]i及组织中水含量明显低于对照组（P＜0．01）；伤后24h[Ca^2 ]i及组织中水含量GDNF组＞MP组及GDNF＋MP组（P＜0．01），MP组与GDNF＋MP组无差异（P＞0．05）；伤后72h的[Ca^2 ]i水平，GDNF组＞MP组＞GDNF＋MP组（P＜0．05）；组织中水含量GDNF组＞MP组及MP＋GDNF组（P＜0．01）；伤后7天[Ca^2 ]i的水平，GDNF组＞MP组＞GDNF＋MP组（P＜0．01）；组织中水含量各治疗组无显著差异（P＞0．05）。结论：GDNF、MP及其联合应用均能降低脊髓组织[Ca^2 ]i水平，减轻组织水肿，作用效果MP超过GDNF，MP联合GDNF治疗脊髓损伤能增强MP的疗效。

Comparative study of GDNF and methyl prednisolone on intracellular free calcium and containing water capacity after spinal cord injury in rats

Objectives:To compare the effect of glial cell line derived neurotrophic factor(GDNF) and methylprednisolone(MP) on intracellular free calcium([Ca 2+ ]i) and capacity of containing water(CCW) after spinal cord injury(SCI). Methods:Forty two SD rats were divided into four groups: control, GDNF,MP and GDNF+MP.GDNF and MP were supplied through subarachnoid cavity, tail vein and both of the above after T 12 segments spinal cord injury by modified Allen crush method. Animals were executed and specimens were collected at 24 h, 72 h and 168 h after SCI.[Ca 2+ ]i and CCW were measured using Fura 2 method. Results:Both [Ca 2+ ]i and CCW of injured spinal cord in GDNF,MP, and GDNF+MP groups were lower than that of the control group at 24 h and 72 h after SCI( P <0.01).Levels of [Ca 2+ ]i and CCW in GDNF group was much higher than that of MP and MP+GDNF groups( P < 0.01 ),but there was no difference between MP group and MP+GDNF group( P >0.05) 24 hours after SCI. Seventy two hours after SCI,[Ca 2+ ]i in GDNF group was higher than that in MP group, MP group was higher than MP+GDNF group( P <0.05).CCW of GDNF group exceeded that of MP and MP+GDNF group( P <0.01).[Ca 2+ ]i in GDNF group was higher than that in MP group, and MP group was higher than MP+GDNF group( P <0.01) 7 days postoperatively, but for CCW, there were no differences among GDNF,MP and MP+GDNF groups( P > 0.05 ). Conclusions: Both GDNF,MP and GDNF + MP groups might reduce [Ca 2+ ]i and CCW of injured spinal cord. The curative effect of MP for SCI preponderate over that of GDNF, the effect of MP could be enhanced by adding GDNF.