Introduction: Recently, sepsis associated muscle wasting, has been reported to worsen disease status and prognosis, and its solution is urgently needed. The aim of this study was to elucidate the molecular mechanisms by adenosine 5’-monophosphate(AMP), which induces a hibernation-like state, contributes to the suppression and recovery of sepsis associated muscle wasting.
Methods: C57BL/6 mice, aged 8-10-weeks, underwent cecum ligation and perforation (CLP) or sham operation and were divided into 3 groups: CLP, CLP+AMP, and CON (sham). The CLP+AMP group received AMP at a dosage of (0.5 mg/g body weight) daily. Grip strength measurements were performed on mouse forelimbs daily for 5 days. Blood samples were collected at 24 hours and skeletal muscles were dissected at 5 days of sepsis. Genetic markers associated with muscle wasting were evaluated by RNA sequencing. Morphological changes were assessed by muscle cross-sectional area (CSA) with tissue staining. C2C12 myoblasts were differentiated into myotube cells over 5 days. On day 3 of differentiation, cells were stimulated with AMP, LPS, IL-1β, LPS+AMP, and IL-1β+AMP, respectively, and immunostaining was performed 48 hours later on day 5 of differentiation. Morphological changes were assessed by measuring the number of fused cells, myotube cell area, and myotube width.
Results: The inflammatory cytokines IL-6 and IL-1β inflammatory cytokines were significantly elevated in the blood of the CLP group (p < 0.05). The wet of tibialis anterior muscle was decreased in the CLP group compared to the CON and CLP+AMP groups after 5 days (p < 0.05). Grip strength was significantly decreased in the CLP group compared to the CON group after day 3 (p < 0.05). CSA measured by tissue staining was significantly decreased in the CLP group but showed recovery in the CLP+AMP group. Real-time PCR showed a significant increase in the expression of Fbxo32, a gene linked to muscle atrophy, in the CLP group (p < 0.05). Immunostaining of C2C12 cells indicated significant reductions in nuclear fusions, myotube area, and myotube width were all significantly decreased by LPS and IL-1β stimulation compared AMP groups (p < 0.05).
Conclusions: AMP suppressed the expression of inflammatory cytokines. It also suggested the possibility of restoring skeletal muscle functionally and morphologically.
