Morin Improves the Bone Histomorphology and Biochemical Markers in an Animal Model of Ovariectomy-Induced Osteoporosis by Suppressing Autophagy and Apoptosis.

Osteoporosis (OP) is the most prevalent metabolic bone disease and an important postmenopausal consequence. This study aimed to investigate the effects of morin, a flavonoid with beneficial properties, on ovariectomy-induced OP. Animals were ovariectomized (OVX) and treated with different doses of morin (15, 30, and 45 mg/kg/day) or estradiol (10 μg/kg/day) for 10 weeks by gavage. Then bone histo-stereology, bone-related biochemical indicators, and gene and protein levels of autophagy and apoptosis-related markers were analyzed. In comparison to controls, OVX significantly decreased the number of osteoblasts (5.78 × 10 vs. 1.66 × 10) and osteocytes (32.55 × 10 vs. 11.92 × 10), whereas increasing the number of osteoclasts (83.38 × 10 vs. 392.1 × 10). Moreover, OVX caused a remarkable decrease in bone structures and Ca, P, and estradiol levels while increasing ALP and OC ( < 0.001). The administration of 45 mg/kg/day morin restored the effects of OP on bone histomorphology and biochemical markers ( < 0.05). Further studies revealed that morin caused a 7.1% and 36.6% decrease in the bone level of LC3 and BECN1 proteins, respectively, compared to the OVX group. Also, morin caused a significant decrease of 47.4% in the CASP3 level and a significant increase of 23.6% in the BCL-2 level compared to OVX animals ( < 0.001). The present findings showed that morin is potentially able to improve the bone-related histomorphological and biochemical changes caused by osteoporosis, which is probably attributed to the suppression of apoptosis- and autophagy-caused cell death.