Light Microscopic and Environmental Scanning Electron Microscopic Study on the Effect of Exercise on Bone Microstructure in Ovariectomized Rats

Introduction: With the onset of menopause, reduced estrogen levels and decreased physical activity created serious problems with resultant osteoporosis and fractures. Recent moves away from hormone replacement therapy suggested exercise, as the simplest and cheapest strategy to treat and prevent osteoporosis. Aim of the Work: The present study aimed to focus (from the histological point of view )on the efficacy of exercise in the amelioration of osteoporotic bone loss in ovariectomized rats with special reference to bone mineral density and bone histomorphometry. Materials and Methods: Forty adult female albino rats were used and divided into four groups. Group I (control group) which were further subdivided into 2 equal subgroups, Ia: received no intervention. Subgroup Ib included nonovariectomized rats experiencing daily exercise training program. Group II (overiectomized rats) which were further subdivided into 2 equal subgroups. Subgroup IIa: were ovariectomized on day 1 of the experiment and sacrificed on day 60 after ovariectomy. Subgroup II b rats were ovariectomized on day 1 of the experiment and experienced daily exercise training starting from day 30 till end of experiment. Exercise training program consisted of swimming for 4 weeks. It started initially for 5min/day and regularly increased until ultimately reached 1hour/day for the last 2 weeks. At the end of experiment, the femur was dissected out; the upper femur epiphysis was obtained and bisected longitudinally. Characterization of mineral presence and density was done using environmental scanning electron microscopy (ESEM) coupled with Energy dispersive x-ray analysis (EDAX). Bone histomophometric analysis was also performed. Results: Subgroup IIa showed significant decrease in the trabecular bone thickness and conversely, significant increase in trabecular seperation compared to control group. Moreover, a marked decrease in bone mineral density was detected. While examination of subgroup II b revealed, significant improvement in trabecular bone thickness and separation compared to subgroup IIa. The bone mineral density was elevated as well. Negative Glial-Fibrillary-Acidic Protein (GFAP) reaction in the full term filum terminale group. In two weeks group; there was positive reaction. In one month group there was strong reaction which persisted with gradual decline in three and six month groups. In one year, GFAP reaction was scanty positive or even negative. Conclusion: From the results of this work, it was concluded that exercise was effective in reducing the risk of osteoporosis in ovariectomized rats.