Exercise effects on pain relief and extracellular matrix production in a rat model of intervertebral disc degeneration

doi:10.3969/j.issn.2095-4344.2017.20.011

Abstract

Abstract:

BACKGROUND: Exercise has been proved to accelerate the proliferation of intervertebral disc cells and extracellular matrix production in healthy rats. For the degenerative intervertebral disc, whether exercise also has positive effects on its cell proliferation, extracellular matrix production or pain relief remains unclear.

OBJECTIVE: To investigate the effect of exercise on the extracellular matrix production in a rat model of intervertebral disc degeneration.

METHODS: A rat model of intervertebral disc degeneration was prepared by Freund’s complete adjuvant injection into the intervertebral disc at L_5-6levels. Then, the model rats were allowed to have a rest for 2 weeks. All rats were then randomly divided into exercise and control groups. Rats in the exercise group were forced to run every day, while the controls allowed free activities in the cage. The behavioral tests were performed at 7, 14, 28, 42, 56 and 70 days after modeling; meanwhile, the intervertebral disc samples were collected used for alcian blue staining and immunohistochemical staining to detect the levels of proteoglycan, aggrecan and collagen type II in the intervertebral disc cells, respectively.

RESULTS AND CONCLUSION: Vocalization threshold on the rat back of punctured disc was significantly decreased, while grooming and wet-dog shaking were significantly increased at 7 days after modeling compared with the baseline (P < 0.05), suggesting that Freund’s complete adjuvant injection successfully induces disc degeneration, hyperalgesia and abnormal behaviors. Further, the vocalization threshold and wet-dog shaking in the exercise group showed significant improvement compared with the control group after 14 days of exercise (P < 0.05), while the grooming was significantly reduced until the 28^th day (P < 0.01), indicating that exercise can alleviate pain caused by disc degeneration in model rats. At 21 days after modeling, the levels of proteoglycan, aggrecan and collagen type II in the nucleus pulposus and annulus fibrosus were significantly decreased compared with the baseline (P < 0.01), indicating the occurrence of disc degeneration. After 14 days of training, the levels of proteoglycan, aggrecan, and collagen type II in the nucleus pulposus and annulus fibrosus in the exercise group were significantly increased compared with the control group (P < 0.01). Moreover, after 8-week exercise, the level of proteoglycan in the nucleus pulposus and annulus fibrosus in the exercise group was increased by 4-5 times compared with the control group, and levels of aggrecan and collagen type II in the nucleus pulposus in the exercise group also was increased by 3-4 times compared with the control group. To conclude, exercise can promote extracellular matrix increased by production by increasing the levels of proteoglycan, aggrecan, and collagen type II in the degenerative intervertebral disc.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Intervertebral Disk Degeneration, Extracellular Matrix, Tissue Engineering

CLC Number:

R318

Luo Hai-jie, Ke Song-jian, Lin Cai-na, Wan Qing, Li Xiao, Liu Cui-cui, Ma Chao, Wu Shao-ling. Exercise effects on pain relief and extracellular matrix production in a rat model of intervertebral disc degeneration[J]. Chinese Journal of Tissue Engineering Research, 2017, 21(20): 3176-3182.

Figures/Tables 2

2.1 实验动物数量分析纳入96只大鼠，随机分为2组，全部进入结果分析，无脱失。 2.2 运动训练对完全弗氏佐剂模型大鼠背部压力痛觉过敏的作用术后第7天与术前相比，2组大鼠在穿刺椎间盘所对应的背部皮肤进行按压引起发声的压力阈值与术前基线值比较显著下降(P < 0.01)。术后第14天大鼠发声的压力阈值较第7天有所上升，但与术前基线值比较仍显著下降 (P < 0.01)。从术后第28天(运动训练2周)开始，运动组压力痛觉过敏症状缓解情况明显优于相应的自然恢复组，差异有显著性意义(P < 0.05)，见图1。 2.3 运动训练对完全弗氏佐剂模型大鼠自发行为异常的影响术后第7天与术前相比，2组大鼠整理毛发的持续时间延长、“湿狗摇动”的次数增加，与术前基线值相比差异有显著性意义(P < 0.05)，见图2。术后第14天2组大鼠整理毛发的持续时间较第7天有所缩短、“湿狗摇动”的次数稍减少，但与术前基线值相比差异仍有显著性意义(P < 0.05)。从术后第42天(运动训练4周)开始，运动组整理毛发的持续时间较相应时间点的自然恢复组短，差异有显著性意义(P < 0.05)，而运动组“湿狗摇动”则从术后第28天(运动训练2周)开始，较相应时间点的自然恢复组明显减少，差异有显著性意义(P < 0.05)。 2.4 运动训练对完全弗氏佐剂模型大鼠椎间盘蛋白多糖合成的影响椎间盘中蛋白多糖被染成蓝色，几乎大部分均匀地分布在髓核区域，少部分在纤维环上，并且含量由纤维环内环逐渐向外环减少，见图3。术后第14天时，2组蛋白多糖的含量与术前基线值相比显著下降(P < 0.01)，且于第21天时含量降至最低(P < 0.01)。从术后第28天(运动训练2周)开始，运动组髓核区域和纤维环的蛋白多糖含量已基本恢复到基线水平，并且与相应时间点的自然恢复组相比差异有显著性意义(P < 0.01)。而经过8周的运动训练后，运动组髓核区域和纤维环的蛋白多糖含量与自然恢复组相比有四至五倍的增加(P < 0.01)，而与术前基线值相比则有三至四倍的增加 (P < 0.01)，见图4。 2.5 运动训练对椎间盘蛋白聚糖和Ⅱ型胶原合成的影响蛋白聚糖和Ⅱ型胶原是髓核基质的重要组成成分。在术后第14天时，与术前基线值相比，运动组和自然恢复组均观察到蛋白聚糖和Ⅱ型胶原明显丢失(P < 0.01)，且于第21天时含量降至最低(P < 0.01)。从术后第28天(运动训练2周)开始，运动组的蛋白聚糖和Ⅱ型胶原含量与自然恢复组相比显著增加(P < 0.01)，并且在运动训练8周时增加量达到了三至四倍，见图5，6。"

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