Terapia com antirreabsortivos e exercícios físicos nas ratas osteoporóticas ovariectomizadas

Abstract

Many treatments have been developed to delay or reverse osteoporosis: antiresorptive, anabolic and physical activities. There are discussions regarding the methods and its synergistic effects. The objective of this study is to evaluate how isolated and synergistic treatments behave in the bones of rats submitted to ovariectomy. For this, 96 Wistar rats were used, divided into 12 experimental groups: OVX4- ovariectomized and follow-up for 4 weeks; OVX8- ovariectomized and followup for 8 weeks; OVX12- ovariectomized and follow-up for 12 weeks; OVXR4- ovariectomized and in the following 4 weeks administered risedronate; OVXR8- ovariectomized and in the following 8 weeks administered risedronate; OVXR12- ovariectomized and in the following 12 weeks administered risedronate; SHAMEsubmitted to simulated surgery and exercises for 12 weeks; SHAMR- submitted to sham surgery and administered risedronate for the following 12 weeks; SHAMREsubmitted to sham surgery and administered risedronate and exercise for the following 12 weeks; OVXE- ovariectomized and exercised on the treadmill for 12 weeks; OVXRE- ovariectomized and administered risedronate and exercised on the treadmill for the following 12 weeks; CONTROL- reference- not submitted to any procedure (only free ambulation in the cage). All groups were euthanized after 12 weeks, except for the animals in groups OVX4 and OVXR4 and OVX8 and OVXR8, which were euthanized at 4 and 8 weeks, respectively. During follow-up, all animals were weighed and had monthly control radiographs taken to assess bone mineral density. After the end of the experiment, blood tests were collected, the left spines and femurs were dissected and submitted to histological analysis. The data were analyzed by statistical tests with a significant level of 5%. The results regarding weight demonstrated that the ovariectomized animals presented a greater weight gain than those in the SHAM groups, particularly in the synergistic treatment groups. Laboratory tests demonstrated a decrease in calcium and an increase in Ca and FA in the OVX groups. Radiographic densitometry demonstrated a decrease in radiographic density in the spine of the ovariectomized animals with an increase in density in the animals submitted to the treatments. Histomorphometry demonstrated higher rates of the BV/TV ratio in the animals submitted to the intervention. It is concluded that physical exercise and the drug have synergistic effects on the bones of ovariectomized rats. The drug risedronate and exercise have no benefits in primary prevention.