Veterans with chronic motor complete spinal cord injury (SCI) invariably have had bone loss and resultant severe sub-lesional osteoporosis and increased fragility fractures. Currently, there is no widely accepted or proven treatment for osteoporosis in non-ambulatory patients with SCI. The efficacy of anti-resorptive agents in the treatment of those with acute SCI has been questioned and ineffective. As a result, there is an urgent need to develop new therapeutic strategies to prevent bone loss and enhance bone quality after sustaining a SCI. The primary objective of this proposal is to determine the efficacy of a recently-discovered muscle factor or myokine named β-aminoisobutyric acid (BAIBA) on reducing bone loss after chronic SCI. BAIBA has been shown to exhibit potent osteogenic properties and to prevent bone loss in tail suspended mice, a model of unloading bone loss. Furthermore, BAIBA produced its favorable osteogenic properties by inhibiting, in osteocytes, oxidative stress and improving mitochondrial function. Importantly, our preliminary findings demonstrate that osteocytes from bones of SCI mice exhibit impaired mitochondrial function and increased oxidative stress. Accordingly, we propose to test the hypothesis that BAIBA administration will restore osteocyte function thus reducing bone loss after chronic SCI. In our study aim, we will elucidate the effects of oral administration of vehicle and different doses of BAIBA on restoring bone mineral density (BMD) and structure in mice after chronic SCI. BAIBA will be administered to 20 week old C57BL/6J wild type male and female sham or SCI mice in drinking water at 0, 50, 100, or 500 mg/kg/day. Treatment will start 35 days after SCI and will continue for 35 days when animals will be sacrificed. Endpoint analyses will include measurement of BMD by Dual energy x-ray absorptiometry (DXA) scanning and bone structure and microarchitecture by microcomputed tomography scanning (Micro-CT). Biochemical analysis of bone turnover markers and factors will also be performed on collected sera and bone marrow (BM) supernatants using specific ELISA. Mechanistically, the effects of BAIBA treatment on oxidative stress will be evaluated on BM supernatants and osteocyte-enriched bone extracts of SCI and control mice using specific oxidative stress assays. The project is expected to identify the optimal therapeutic dose of BAIBA that will attenuate the deleterious effects of immobilization on the skeleton of SCI animals. This application has the potential of discovering a new therapeutic strategy that may overcome the challenge of severe osteoporosis in Veterans with SCI specifically many years after injury. We propose the following specific aim: Aim: To determine the effects of BAIBA on restoring skeletal integrity after chronic SCI.