A型肉毒毒素干预对脊髓损伤大鼠小腿肌群病理特征的影响

Effects of botulinum toxin type A injection for pathological characteristic of calf in rats with spinal cord injure

目的探讨A型肉毒毒素干预对SCI后大鼠小腿肌病理特征及运动功能的影响。方法36只SD雄性大鼠按随机数字表法分配至正常对照组、12周对照组、生理盐水（NS）干预组和肉毒毒素（BT）干预组。NS/BT干预组按干预时间不同又分设2个亚组（2周-NS，2周-BT，8周-NS，8周-BT）。正常对照组和12周对照组大鼠不予注射药物；NS/BT干预组，按上述时间点（2周、8周）分别给予A型肉毒毒素（BoNT-A）/生理盐水注射至大鼠右腓肠肌（GM）。大鼠小腿GM和比目鱼肌（Sol）标本均进行肌重测量及蛋白电泳分析（MyHC）等病理检测。结果BT干预组大鼠右GM及Sol肌重均较其他各组大鼠右GM及Sol明显下降（P≤0.05）。BT干预组大鼠右GM和右Sol的MyHC的分型占比较其他三组显著改变，2周-BT亚组大鼠右GM和右Sol的MyHC的分型占比与8周-BT亚组大鼠的分型占比亦有不同。BT干预组大鼠非注射侧GM的MyHC的分型占较正常对照组发生变化。2周-BT亚组注射侧GM较8周-BT亚组大鼠非注射侧GM的MyHC分型占比改变显著。结论BoNT-A注射不仅会引起SCI大鼠同侧GM发生病理改变，也会致同侧Sol及对侧GM发生病理改变；早期（2周）BoNT-A注射干预对GM及Sol的MyHC亚型转变影响显著。

Objective To explore the effect of BoTN-A on pathological characteristics of calf （GM） and motor function of ankle dorsiflexors in SCI model rats.Methods Thirty-six SD male rats （weight 260-280 g） were randomly allocated into normal control group and 12w-control group, NS-injection group and BT-injection group in this study.NS/BT-injection groups were divided into two subgroups separately （2w-NS, 2w-BT, 8w-NS, 8w-BT）. No injection was applied in normal control group or 12w-control group.Saline/BoTN-A was injected in right GM in NS/BT-injection group at two different time points（2w, 8w）. GM and Sol on right side of rats would be forwarded for pathologicalexaminations, such as muscle weight, myosin heavy chain （MyHC） electrophoretic analysisat the 12th week.Results Compared with the other three groups, the muscle weights of GM and Sol in the BT-injection group significantly decreased.MyHC type ratioof GM and Sol on the right side in the BT-injection group also significantlychanged.According to subgroup comparisons, MyHC type ratio of GM and Sol on the injectedside in the 2w-BT subgroup was significant different from that of the 8w-BT subgroup.MyHC type ratios of GM on the non-injected side in the BT injection group also changed more than normal control group.The change of MyHC type ratio of non-injected GM was significantly higher in the 2 week-BT subgroup than that in the 8-week subgroup.Conclusions BoNT-A intervention resulted in pathological changes not only in the injected GM in SCI rats, but also in non-injected GM and non-injected Sol.The effects of earlier （2 weeks） BoTN-A intervention on pathologic characteristicsof GM and Sol were larger than that of later intervention.