Reactive hyperplasia of glial cells induced by spinal cord injury in a rat model

doi:10.3969/j.issn.2095-4344.2016.40.011

Abstract

Abstract:

BACKGROUND: The nervous reconstruction and repair after spinal cord injury have become a research hotspot.

OBJECTIVE: To investigate the change rule of neurogliocyte reactive hyperplasia after spinal cord injury.

METHODS: Forty-two adult male Sprague-Dawley rats were selected and equivalently randomized into seven groups: normal control group (no intervention), sham operation group (lamina decompression) and operation groups (postoperative 1, 7, 14, 21 and 28 days). After the establishment of spinal cord injury models, the rats were sacrificed at each corresponding time point. The functional recovery of the rat hind limbs was evaluated by Basso, Beattie and Bresnahan scores, and complete spinal cord tissue was removed to undergo hematoxylin-eosin staining, immunohistochemistry staining and immunofluorescence staining.

RESULTS AND CONCLUSION: (1) Basso, Beattie and Bresnahan scores showed that rats in the normal control and sham operation groups had normal neurologic function. Rats at 1 day after spinal cord injury paralyzed completely, the neurologic function of hind limbs began to recover gradually at the 7^th day, and the recovery became most obvious at the 14^th day, which had no significant differences compared with the 21^st and 28^th days. (2) Hematoxylin-eosin staining found that the diffuse hemorrhage and neuronal necrosis were observed in the injured area at 1 day after operation; inflammatory cell infiltration and some vacuoles appeared at the 7^th day, and the hemorrhage was absorbed gradually; the hemorrhage disappeared completely and capsule cavity formed at the 14^th day; up to the 28^thday, spinal cord structure was completely destroyed and that was replaced by cicatricial tissue accompanying with a large cavity. (3) Immunohistochemistry staining showed that the astrocyte in damaged area proliferated with the cell synapse increasing, which was most overt at the14^th day; the axon clearance widened and the structure was in disorder at the 7^th day, and the myelin sheath in the damaged area was destroyed at the 21^st day. (4) Immunofluorescence staining showed that there were numerous visible glial fibrillary acidic protein⁺/nestin⁺ cells in the injured area at 14 days after operation. (5) These results suggest that glial cell hyperplasia and hypertrophy, the up-regulated expressions of glial fibrillary acidic protein and nest protein are advantageous to the early repair of spinal cord injury.

Key words: Animals, Laboratory, Spinal Cord Injuries, Cicatrix, Tissue Engineering

CLC Number:

R318

Fan Xu-hui, Yang Bo, Hu Xiang, Guan Fang-xia. Reactive hyperplasia of glial cells induced by spinal cord injury in a rat model[J]. Chinese Journal of Tissue Engineering Research, 2016, 20(40): 6001-6006.

Figures/Tables 2

2.1 实验动物数量分析 42只大鼠均进入结果分析。 2.2 各组运动功能恢复评分正常对照组及假手术组大鼠后肢运动功能正常，BBB评分为21。脊髓损伤后1 d组后肢完全瘫痪，BBB评分为0；脊髓损伤后7 d组双下肢功能好转，BBB评分为8.50±1.04；脊髓损伤后14 d组双下肢功能明显恢复，BBB评分为18.60±2.06；脊髓损伤后21，28 d组与脊髓损伤后14 d组变化不明显，BBB评分分别为18.80±1.72，19.5±1.51。脊髓损伤大鼠BBB评分均低于正常对照组(P < 0.05)，脊髓损伤后28 d组BBB评分高于脊髓损伤后1，7 d组(P < 0.05)。 2.3 各组脊髓损伤部位组织变化正常脊髓中神经元结构好，数量多，细胞核大，核仁明显；脊髓损伤后1 d组脊髓内弥漫性出血，细胞大量坏死；脊髓损伤后7 d组脊髓内出血逐渐吸收，炎症细胞浸润，部分细胞形成空泡；脊髓损伤后14 d组出血完全吸收，脊髓结构破坏，囊腔形成；脊髓损伤后21 d组脊髓结构严重破坏，空腔出现；脊髓损伤后28 d组脊髓结构完全破坏，巨大空洞形成，局部大量瘢痕组织形成，见图1。 2.4 各组GFAP和巢蛋白荧光染色脊髓损伤后14 d组脊髓中央管周围室管膜区及损伤临近区域可见大量巢蛋白和GFAP表达，室管膜区周围可见部分GFAP/巢蛋白阳性双标细胞，见图2。 2.5 各组GFAP免疫组化染色正常脊髓切片可见星形胶质细胞染色成棕黄色，突触细长，呈蜘蛛形；脊髓损伤后1 d组损伤处星形胶质细胞开始增多，少量炎症细胞浸润；脊髓损伤后7 d组星形胶质细胞胞体增大，突触增多、延长，染色加深；脊髓损伤后14 d组胞核明显，胞体肥大染色深，突触相互连接；脊髓损伤后21 d组星形胶质细胞部分增生，脊髓损伤后28 d组可见星形胶质细胞进一步增生，受损局部囊腔形成，细胞之间连接成网，见图3。 2.6 各组髓鞘碱性蛋白免疫组织化学染色正常脊髓纵切面为连续、完整的结构；脊髓损伤后1 d组可见部分髓鞘破坏，脊髓结构疏松、紊乱；脊髓损伤后7 d组可见轴突间隙稍增大，结构紊乱，空泡形成；脊髓损伤后21 d组轴突间隙进一步增大，大空洞形成，髓鞘结构破坏，见图4。"

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