甲基强的松龙治疗大鼠急性脊髓损伤后对骨密度及生物力学的影响

目的:观察大鼠急性脊髓损伤后大剂量甲基强的松龙(methylprednisolone,MP)冲击疗法对大鼠骨密度及生物力学的影响。方法:46只成年健康SD大鼠随机分为对照组、模型组、治疗组等3组。按改良Allen's法建立大鼠急性脊髓损伤模型。治疗组伤后30min经腹膜腔注入MP30mg/kg,以后每小时注入MP5.4mg/kg,维持24h;模型组应用生理盐水替代MP,处理方法同治疗组。观察模型组与治疗组大鼠在伤后1、3和6个月BBB运动功能评分、各组L4椎体、股骨不同部位骨密度及生物力学参数的变化。结果:术后各时间点模型组与治疗组BBB评分总体呈增高趋势,治疗组在各个时间点BBB神经行为学评分均优于模型组(P<0.05,P<0.01)。术后1、3、6个月,模型组与治疗组大鼠股骨骨密度均显著下降(P<0.05,P<0.01);术后6个月,与模型比较,治疗组股骨、腰椎骨密度均显著下降(P<0.05)。术后6个月,对模型与治疗组大鼠的右侧股骨最大荷载、第4腰椎结构强度均显著降低(P<0.01);与模型组相比,治疗组的右侧股骨最大荷载、第4腰椎结构强度降低,结果具有显著性差异(P<0.05)。结论:模型组及治疗组均可导致骨质疏松的发生,但大剂量MP对大鼠远期骨密度及生物力学有不利影响。

MP Effect on bone density and biomechanics of rats with acute spinal cord injury

Objective： To investigate the effect of high dose MP on bone density and biomeehanics changes after acute spinal cord injury（ASCI）. Methods. A total of 46 adult rats were randomly divided into three groups, namely, the control group （CG）, the model group （MG）, and the experimental group （EG）. After anesthesia, T8 vertebrae plate resection were performed to rats in both CG and EG with spi- nal cords injury by Allen method. Thirty minutes after ASCI, the subjects in experimental group received MP injection through intraperitoneal with dosage of 30 mg/kg. Then a dosage of 5.4 mg/kg of MP was given through intraperitoneal injection every hour in 24 hours. The subjects in the model group received normal saline instead of MP with the same method. A detection of both Basso, Beattie and Bresnahan （BBB） locomotor rating scaling, bone density and biomechanics was performed .to the 1.4 vertebral body and the femur of rats 1, 3 and 6 months following operation, respectively. Results. BBB scale, after oper- ation, the scale of groups MG and EG was increased over time; group EG was significantly higher than group MG from 1, 3, 6 month （P〈0.05, P〈0.01） ; bone density in the femur and the lumbar vertebra ofratsin MG and EG deceased dramatically 1, 3, 6 months postoperatively （P〈0.05, P%0.01）. Compared with MG, bone density in both femur and the lumbar vertebra in EC deceased dramatically 6 months postoperatively （P〈0.05）. The femur＇s maximum load and structural strength of vertebra were significantly deceased 6 months postoperatively （P〈0.01）. Compared with MG, there was significant decrease about the femur＇s maximum load, the L4 vertebral structural strength maximum load （P〈0.05）. Qonclu- sions： Both MG and EG can result in osteoporosis, but the high-dose MP has long-term adverse effect on bone density and biomechanics in rats.