Effects of mechanical stress on bone metabolism and life span in stroke-prone spontaneously hypertensive rats

研究了跳高运动对卒中易发自发性高血压大鼠钙代谢和寿命的影响。据报道，随着年龄的增长，他们逐渐成为高血压，死于脑卒中，并伴有钙代谢异常。推测钙代谢异常是其血管疾病的重要因素之一。另一方面，在我之前的研究中，大鼠的跳跃运动有效地增加了局部骨骼中的钙积累。因此，我假设跳跃运动影响了SHRSP的全身钙代谢。首先，研究了跳远运动对老龄人口寿命的影响。虽然我试了两次，但我没有发现锻炼组和久坐组的寿命有显著差异。其次，我研究了跳跃运动对SHRSP钙代谢的影响。与正常大鼠相比，跳远运动增加了SHRSP大鼠下肢骨量。然而，跳远运动不影响血清钙和甲状旁腺激素，但显著降低了SHRSP的血清磷酸盐。这些结果表明跳跃运动不会改变全身钙代谢。再次，研究跳跃运动对SHRSP大鼠和正常大鼠血清骨细胞相关细胞因子或蛋白水平的影响。我没有发现骨桥蛋白、sRANKL、基质Gla蛋白和骨保护素在SHRSP运动或正常大鼠中有明显变化。我也测量了脂质代谢，但也没有发现跳跃运动的显著影响。综上所述，跳远运动虽然增加了局部骨量，但并未改变全身钙代谢。它也不影响SHRSP的寿命。

I investigated the effects of jump exercise on calcium metabolism and life span in stroke-prone spontaneously hypertensive rats(SHRSP). It was reported SHRSP became hypertension as they grew and was died by cerebral apoplexy, and they also had abnormal calcium metabolism. It was assumed that the abnormal calcium metabolism was one of important factors of their vascular disease. On the other hand, in my previous study, jump exercise in rats effectively gained calcium accumulation in regional bones. Thus, I assumed that jump exercise influenced whole body calcium metabolism in SHRSP.Firstly, I investigated the effect of jump exercise on life span in SHRSP. Although I tried twice, I did not find significant difference in life span between exercised and sedentary group.Secondly, I investigated the effect of jump exercise on calcium metabolism in SHRSP. Jump exercise increased bone mass of lower limb in SHRSP like in normal rats. However, jump exercise did not affect serum calcium and parathyroid hormone although it significantly decreased serum phosphate in SHRSP. These results suggested that jump exercise did not alter whole body calcium metabolism.Thirdly, I investigated the effect of jump exercise on serum cytokine or protein level associated with osteocyte in SHRSP or normal rats. I did not find significant changes in osteopontin, sRANKL, matrix Gla protein and osteoprotegerin in exercised SHRSP or normal rats. I also measured lipid metabolism but also did not find the significant influences of jump exercise. In conclusion, jump exercise in SHRSP did not change whole body calcium metabolism although it increase local bone mass. It also did not influence life span in SHRSP.