Chronic inflammation associated with obesity exacerbates bone loss in mice

Abstract Dysfunctional adipose tissue characterized by abnormal inflammatory cytokine production during obesity, is linked to several metabolic disorders including bone loss. An increase in bone fracture incidence due to increased rates of obesity is becoming a significant new health concern. However, it is still obscure whether obesity accelerates bone loss. Herein, we have investigated the systemic weight gain, cytokine production, bone turnover markers and femur bone micro-architecture in high-fat diet (HFD) fed obese mice. HFD mice exhibited excessive visceral fat accumulation (2.4 fold) in the peritoneal cavity and increased body weight (2.1 fold) compared to regular chow diet (RCD) fed mice. The serum levels of pro-inflammatory cytokine IL-6 was increased approximately 8-fold in HFD mice compared to RCD mice. The serum bone turnover marker, C-terminal telopeptides of collagen (CTx), was almost 2-fold higher in HFD mice compared to RCD mice. Further, radiological studies from micro computed tomography (micro-CT) of femur suggests that HFD mice exhibited considerably reduced bone volume fraction (BV/TV) and cortical thickness compared to RCD mice. These results suggest the chronic inflammation associated with many metabolic disorders such as obesity may accelerate bone loss.