Objective To study the effect of vibration on the degeneration of the rat lumbar intervertebral disc tissue and bone mineral density (BMD) of the femur. Methods Forty 6-week-old male SD rats were randomly divided into 4 groups : normal group (n = 10) and 3 vibration experimental groups (n =30). The vibration rate of the 3 groups was 5 Hz, 20 Hz, and 60 Hz, respectively. And each group had 10 rats. All the rats in vibration experimental groups received vertical vibration training, while the rats in normal group were fed under the same conditions without any vibration intervention. The area for exercise and the whole feeding time were same for all the rats. BMD detection of the femur was performed on week 12. Then all rats were sacrificed and the intervertebral disc (L5-L6) were collected, fixed, and sliced. Morphology of the rat intervertebral disc tissue was observed using HE staining. The apoptosis of the disc was detected using TUNEL method ( FITC + POD). Results The amount of intervertebral disc nucleus pulposus cells in vibration groups was less than that in normal group. The mean optical density value of positive particles and the percentage of positive cells detected using TUNEL method increased. The difference was statistically significant ( P ＜ 0. 05). BMD of the femur in all groups showed no significant difference (P ＞ 0. 05 ). Conclusion Mechanical vibration of a certain rate can affect the degeneration of the rat lumbar intervertebral disc. In a certain range, along with the increase of the vibration frequency, the cell apoptosis in rat intervertebral disc in vibration experimental groups increases. The degeneration of the intervertebral disc accelerates. But vertical vibration of a certain rate has no significant effect on BMD of the femur in healthy young rats.%目的 研究振动对大鼠椎间盘细胞凋亡及股骨骨密度的影响.方法 选用40只6周龄雄性SD大鼠,随机分成4组:正常对照组10只;振动实验组30只(分别为振动频率5 Hz 10只,振动频率20 Hz 10只,振动频率60 Hz 10只).对实验组动物进行垂直振动训练,正常对照组不进行振动干预,置于与实验组相同环境下,相同面积围栏内自由活动,时间同实验组.12周后对各组大鼠股骨进行 BMD检查,然后将大鼠处死,取出(L5-L6)椎间盘组织,固定、切片.对各组大鼠椎间盘标本组织进行形态学观察(HE染色);TUNEL检测凋亡(FITC+POD).结果 振动实验组大鼠与正常组大鼠比较椎间盘髓核细胞数减少;TUNEL检测阳性细胞的百分率和阳性颗粒的平均光密度值增高,差异均有统计学意义(P＜0.05).而各组大鼠股骨BMD无显著性差异(P＞0.05).结论 一定频率的垂直机械振动可以对大鼠椎间盘髓核细胞凋亡产生影响;且在一定的范围内,随着振动频率的增加,相应振动实验组大鼠椎间盘髓核细胞凋亡增多,椎间盘组织退变加速.而一定频率的垂直振动对健康幼龄大鼠股骨BMD影响不显著.
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