Poly(D, L-lactic-co-glycolic acid)-based microspheres loaded with camphor regulate skeletal muscle atrophy

As effective treatments for sarcopenia other than exercise have not yet been established, research is needed on treatment methods using drugs that can control muscle atrophy. Therefore, in this study, we aimed to assess the use of intramuscular sustained-release drug delivery systems and direct intramuscular injection for the control of muscle atrophy. First, we evaluated the inhibitory effects of camphor on skeletal muscle atrophy in vitro. L6 skeletal muscle cells were analyzed by WST-1 cell viability, 3D tomographic lipid accumulation, and mitochondrial length. These results indicated that camphor significantly regulates L6 cell atrophy. Next, we established poly(lactic-co-glycolic acid) (PLGA)-based microspheres loaded with camphor (PLGA-camphor), with each PLGA-camphor microsphere have a size of ~ 66–75 μm. Camphor was released ~ 93.29% over 10 days. Finally, we administered the PLGA-camphor by intramuscular injection in the starved fed mice model and performed immunohistological and histological analyses. The results indicate that PLGA-camphor is able to significantly regulate skeletal muscle atrophy in vivo. Our results suggest that PLGA-camphor may affect skeletal muscle atrophy.

In the present study, our research findings indicate that camphor significantly reduces muscle atrophy in vitro. It used gravity to load camphor into PLGA-based microspheres, which were 66–75 μm in size. The sustained release properties of PLGA-camphor microsphere were shown to release 93.29% of camphor over ten days. When directly injected into the muscle of mice with muscular dystrophy, the PLGA-camphor microsphere resulted in a noteworthy reduction in muscle atrophy, particularly in the starved-induced muscle atrophy model mice. Our results suggest that PLGA-camphor microsphere could be a promising method for addressing skeletal muscle atrophy.