摘要：Weight-bearing and physical activity are important mechanical stimuli for bone metabolism. The current study was carried out to investigate the effect of compulsive running exercise on bone mineral density (BMD) and bone metabolism in the growing male Stroke-Prone Spontaneously Hypertensive Rat (SHRSP). Twelve SHRSP aged 7 weeks were randomly divided into a sedentary control group (C-group, n=6) and a compulsive running exercise group (R-group; 17 m/min., 60 min./day, 5 days/week for 12 weeks, n=6). Measured responses to the training were total and femoral BMD (by DEXA; DPXL, Lunar, USA) and the mechanical strength of bone (MSB, by three point-bending test; AGS-100D, Shimazu. Japan). The metabolism markers of bone such as alkaline phosphatase (AlP), tartrate-resistant acid phosphatase (TrAcP), intact parathyroid hormone (i-PTH), calcium (Ca) and phosphate (P) were measured. Compared with the C-group, the changes in body weight tended to decrease in the R-group after the age of 10 weeks (P<0.001), and femoral BMD (P<0.05) and bone mineral content (BMC) (P<0.01) in the R-group were shown to be significantly lower than in the C group. Most measurement parameters of the femora, including bone weight (P<0.001), bone length (P<0.001), MSB (P<0.01), femoral Ca (P<0.001), and P (P<0.001) in the R-group were significantly lower than in the C-group. Although serum Ca concentration remained unchanged in both groups, AlP in the R-group was significantly higher than in the C-group (P<0.01), and TrAcP tended to increase in the R-group. These results suggest that compulsive running exercise for 12 weeks leads to the high bone turnover and inhibits the deposition of Ca and P in the bone, which eventually induces osteopenia in growing SHRSP.
关键词：stroke-prone spontaneously hypertensive rat (SHRSP) ; bone mineral density (BMD) ; bone metabolism ; running exercise ; osteopenia ; mechanical bone strength
