The reduction in estrogen levels results in a decrease in bone density at menopause. Irisin is a myokine that modulates the benefits of exercise, which may include bone health. This study was planned to examine irisin’s impact in preventing osteoporosis after ovariectomy. 4 groups of female albino rats (10 rats/group): control, sham-operated, ovariectomized (OVX-control), and OVX-irisin-treated. Serum levels of bone markers [osteocalcin (OC), bone alkaline phosphatase (BALP), tartrate-resistant acid phosphatase (TRAP), calcium (Ca++), phosphorus (P)], glucose, and insulin were being measured. Body mass index, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), dry and ash femur weight, and bone contents of Ca++ and P were investigated. The femur was examined histopathologically. The OVX-control group showed an increase in serum levels of OC, BALP, TRAP, calcium, phosphorus, BMI, glucose, insulin, and HOMA-IR ( P < 0.05 ) and a reduction in dry and ash weight of the femur, the concentration of calcium and phosphorus content in bone ash ( P < 0.05 ). The OVX-irisin-treated group exhibited a decrease in serum levels of OC, BALP and TRAP, calcium, phosphorus, BMI, glucose, insulin, HOMA-IR ( P < 0.05 ), and a rise in dry and ash weight of the femur, the concentration of calcium and phosphorus in bone ash ( P < 0.05 ). Histological examination of the distal femur diaphysis of the OVX-irisin-treated group exhibited proper bone architecture and density compared with that of the OVX-control group. It is concluded that irisin treatment in the OVX rats safeguarded the regular bone architecture and normal levels of serum bone biomarkers. Irisin may be a possible novel target in the prohibition of postmenopausal osteoporosis.

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A strong link between obesity, hypercoagulability and thrombogenesis, had been recognized. Chemerin is a novel adipokine that has been activated by the coagulation process and suggested to play an important role in the pathogenesis of metabolic syndrome. We aimed to identify the possible relationship between chemerin levels and haemostatic changes in the high fat diet (HFD) fed rats. A total number of 20 adult male albino rats were divided into two groups of 10 rats each. Group I, rats served as controls; Group II: rats received high fat diet (58% fat) for 8 weeks. In both groups, serum levels of glucose, insulin, chemerin, total cholesterol (TC), triglycerides (TG), HDL, LDL were measured. As well as the bleeding time (BT), whole blood clotting time (WBCT), Prothrombin time (PT), Activated partial thromboplastin time (aPTT), fibrinogen level and C-reactive protein (CRP) were measured. Moreover HOMA-IR was calculated for both groups. The results of the current study revealed that chemerine level increased significantly in the HFD-fed rats (p< 0.001). In addition, a significant positive correlation was detected for the serum chemerin levels with body weight, insulin levels, HOMA-IR, the levels of TC, TG, LDL and CRP, while a significant negative correlation was found between its levels and serum levels of HDL. Moreover chemerin was correlated negatively with the BT, WBCT, PT, aPTT and positively correlated with plasma fibrinogen, while there was insignificant correlation with platelet count. These results suggested that chemerin may represent a novel link between obesity and its haemostatic and atherogenic complication.

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