Muscle atrophy and long bone osteopenia are attenuated with n‐3 PUFA in a mouse model of hindlimb suspension

Abstract

Muscle atrophy and osteopenia are common issues associated with aging and disease. This study was conducted to evaluate the effects of long chain n‐3 PUFA [eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids] on muscle and bone loss in a mouse model of induced hindlimb atrophy. Mouse hindlimb suspension (HS) is used as a disuse model to induce muscle atrophy and bone loss compared to weight bearing (WB). Six‐wk‐old male mice (ND4 Swiss Webster) were fed a control (n‐6 PUFA, n= 26), a moderate n‐3 PUFA (EPA + DHA 12 g/kg, n = 20), or a high n‐3 PUFA (19.4 g/kg, n= 21) diet for 2 wks. After pre‐feeding, mice were subjected to a baseline DEXA scan and then assigned to the WB or HS groups. Upon 14 days of HS or continued WB, mice were anesthetized for a repeated DEXA scan after which the mice were euthanized, and tissues were collected for analyses. Mice fed n‐3 PUFA demonstrated an elevation of EPA and DHA and reduced arachidonate in serum and tissues. HS resulted in fat, muscle mass and bone mineral content (BMC) losses. Bone ash was conserved in the HS n‐3 PUFA fed groups compared to control HS mice, which supports the protection of BMC/body wt also found in the n‐3 fed groups. There was no additional protection of bone in the high n‐3 diet group compared to the moderate group. Based on this study in mice and other investigations with rodents, the n‐3 PUFA appear to attenuate the physiological changes that occur with HS. Supported by USDA funds.