Effects of Propranolol and <i>Lactobacillus rhamnosus</i> on Bone Tissue and Blood Parameters in Ovariectomized Rats

Background: Osteoporosis is a chronic metabolic disease that leads to decreased bone mass due to an imbalance in bone resorption/formation. The aim of this research was to evaluate the effect of Lactobacillus rhamnosus and propranolol on disorders caused by this disease. Methods: Forty female rats (250±15 g) were divided into control and ovariectomy groups, as well as ovariectomy treated with probiotics, propranolol, and probiotics with propranolol groups. Blood parameters, concentration of parathyroid hormone, alkaline phosphatase (ALP) activity, and bone calcium (Ca) and phosphorus (P) levels were measured after the treatment period. The histopathological changes in bone were compared among the experimental groups. Results: No significant changes were observed in the blood parameters among the groups. Despite the significant increase in the parathyroid hormone and ALP levels in ovariectomized rats, in the treatment groups (especially treatment with both probiotics and propranolol), the level of these two factors decreased significantly. Ca and P concentrations also showed a significant increase in the treatment group with probiotics and propranolol compared to the ovariectomy group. Histopathological studies demonstrated an increase in the thickness of trabeculae, the number of bone cells, and the repair of the diaphysis in rats treated with probiotics and propranolol. Conclusion: It seems that L. rhamnosus and propranolol, by inhibiting the stimulation of the sympathetic system and increasing the reabsorption of minerals from the intestine, led to the inhibition of osteoclastogenesis and the increase of the bone mineral content, followed by the improvement of disorders caused by osteoporosis.