Bone Microstructural Deterioration and miR-155/RHOA-Mediated Osteoclastogenesis in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is known to increase the risk of fragility fractures; however, the underlying mechanism is still elusive. Reduced miR-155 and elevated RHOA are known to drive bone resorption, but their role in T2DM remains unclear. This study investigates bone remodeling imbalances in T2DM through miR-155 and RHOA expression profiling. Three-month-old female Wistar rats were fed a high-calorie diet for 3 weeks, followed by intraperitoneal injections of two lower doses of streptozotocin at weekly intervals to induce T2DM. Bone analysis from diabetic rats tested using qRT-PCR showed significantly reduced miR-155 levels and elevated RHOA. Histological analysis showed a 12.65% increase in Tb.Sp, 10.07% decrease in Tb.Th, and significant increase (p < 0.05) in apoptotic osteocytes. The bone turnover marker CTx-1 level was increased by 20.84%, and RANKL levels were significantly increased in T2DM. IL-1β and TNF-α were increased in T2DM. Bone resorption is more likely to occur in T2DM as both IL-1β and TNF-α work synergistically to promote osteoclastogenesis. MiR-155 could be an important modulator of bone remodeling in T2DM and a potential therapeutic target for diabetic osteopathy.