Abstract
Postmenopausal osteoporosis is a subclinical disease and a global public health disorder associated with morbidity, mortality and deterioration of the quality of life. This study was designed to investigate the effect of omega-3 fatty acid on osteoanabolic markers and bone-resorbing cytokines in ovariectomized (OVX) rats. Forty-eight female Wistar rats weighing between 180-190g were either ovariectomized (n=40) or sham-operated (n=8). The animals were divided into six groups (n = 8): Control, OVX, OVX + Omega-3 fatty acid (100 mg/kg bd wt), OVX + Omega-3 fatty acid (200 mg/kg bd wt), OVX + Omega-3 fatty acid (400 mg/kg bd wt) and OVX + Alendronate (10 mg/kg bd wt). At the end of eight weeks of study period, body weight gain, serum estrogen, osteoananolic markers, bone-resorbing cytokines and anthropometric parameters were determined. The result indicated that treatment of OVX rats with omega-3 fatty acid significantly (p<0.05) reduced excessive body weight gain compared to untreated OVX rats. Similarly, treatment of OVX rats with different concentrations of omega-3 fatty acid significantly (p<0.05) improved estrogen level and reduced RANKL level when compared to untreated OVX rats. Likewise, treatment of OVX rats with omega-3 fatty acid significantly (p<0.05) suppressed IL-6 and TNF-α levels when compared to untreated OVX rats. In addition, omega-3 significantly (p<0.05) improved femur bone mineralization and anthropometric indices when compared to the untreated OVX rats. However, Omega-3 fatty acid did not show any significant (p>0.05) effect on femur length. This study demonstrated that omega-3 fatty acid exhibits potential anti-bone loss activities through improve estrogen level, reduced bone resorbing cytokines expression, alleviates uterine weight loss and enhance bone mineralization in OVX rats. Altogether, these data demonstrated that omega-3 fatty acid could be a beneficial therapeutic agent against post-menopausal bone loss in OVX rats.

Key words: Omega-3 fatty acid, Ovariectomized rats, Estrogen, Osteoanabolic markers, Bone-resorbing cytokines, Mineralization