Combined use of modified chitosan and methylprednisolone promotes repair of sciatic nerve injuries in rats

doi:10.3969/j.issn.2095-4344.2013.47.011

Abstract

Abstract:

BACKGROUND: Previous studies have shown that chitosan can promote the repair of peripheral nerve injury and methylprednisolone can improve the microenvironment around nerve injuries, which are commonly used in clinical treatment of acute central nervous system injury.
OBJECTIVE: To observe the effects of modified chitosan and methylprednisolone combination on repair of sciatic nerve injury in rats.
METHODS: The rat sciatic nerve was transected and microscopically anastomosed immediately. Then, modified chitosan, methylprednisolone, methylprednisolone+modified chitosan, and saline were injected respectively around the anastomosis site, compared with the sham surgery group.
RESULTS AND CONCLUSION: Compared with other groups, the combination group showed shorter claw extending reflex recovery time (P < 0.05). Significant differences were found between the combination group and other groups in nerve conduction velocity, the remnant rate of gastrocnemius wet weight, the diameter and section area of gastrocnemius cells (P < 0.05). The nerve fibers through the anastomotic site were significantly increased, with consistent thickness and arrangement and less neurodegeneration when observed 12 weeks after operation. In conclusion, the modified chitosan combined with methylprednisolone could significantly promote the sciatic nerve repair.

Key words: chitosan, sciatic nerve, nerve fibers, neural conduction, regeneration

CLC Number:

R318

Lu Wei, Zeng Qing-min, Wu Jing-ping, Zhang Xin-chao. Combined use of modified chitosan and methylprednisolone promotes repair of sciatic nerve injuries in rats[J]. Chinese Journal of Tissue Engineering Research, 2013, 17(47): 8209-8214.

Figures/Tables 4

湿质量测定结果显示：取材时发现在神经损伤部位附近，联合治疗组比其他建模组组织解剖清晰，组织粘连较少，瘢痕形成较少，无明显神经瘤形成。腓肠肌大体观察显示：假手术组最饱满，有光泽与弹性，联合治疗组次之。随着建模后时间延长，腓肠肌湿质量残存率逐渐下降，其中生理盐水对照组下降最快，改性壳聚糖组及甲基泼尼松龙组稍慢，联合治疗组最慢。改性壳聚糖组和甲基泼尼松龙组之间的残存率差异无显著性意义。联合治疗组与其他建模组比较，腓肠肌湿质量残存率下降较慢(P < 0.05)。见表3。通过不同组别的苏木精-伊红染色结果可以看出, 随着手术时间延长，建模各组肌细胞直径及截面积呈进行性缩小；同一时间点生理盐水对照组比联合治疗组肌细胞直径及截面积有更大萎缩(P < 0.05)；与假手术组比较，同一时间点上生理盐水组大鼠腓肠肌肌细胞直径、截面积的变化最大，改性壳聚糖及甲基泼尼松龙组居中, 联合治疗组的变化最滞后，见表4。 2.5 坐骨神经损伤大鼠经改性壳聚糖及甲基泼尼松龙治疗后坐骨神经组织学变化建模后12周，坐骨神经病理组织切片光学显微镜观察可见：假手术组神经纤维数量多，直径粗，排列整齐，连续完整，方向性好，未见明显浆细胞和淋巴细胞浸润。生理盐水对照组神经纤维稀疏细小，粗细不均，排列紊乱，呈旋涡样生长，断裂，没有规律，而且方向性差，炎细胞浸润明显。联合治疗组神经纤维数量较多，直径较粗，排列尚可，方向性较好，局部有浆细胞和淋巴细胞浸润，且夹杂着嗜中性细胞和巨噬细胞。而改性壳聚糖及甲基泼尼松龙组介于联合治疗组及生理盐水组之间。并且随着建模后时间延长，4个干预组吻合口粘连及增生情况分别较前逐渐改善。建模后12周，透射电镜观察结果显示：假手术组镜下可见神经纤维无分散，排列有序，髓鞘境界清晰，未见髓鞘脱失。生理盐水组可见神经纤维、树突、轴突及细胞器均严重变性及坏死，膜结构不清，多见空泡状改变，髓鞘排列杂乱、相互融合、溶解，髓鞘完整性严重破坏。联合治疗组可见神经纤维束及树突、轴突、胞体等结构，细胞膜及细胞器均较清楚，纤维排列稍紊乱，胞体内膜结构及形态均接近正常，部分胞体轻度水肿及变性。改性壳聚糖组可见神经纤维排列尚有序，未见明显变性，部分细胞器变性，部分膜结构不清，欠光滑，细胞器变性变形，可见空泡变，部分染色质凝集固缩，但优于假手术组及生理盐水组。甲基泼尼松龙组镜下所见类似于改性壳聚糖组。见图1。"

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