Effects Of Sleep Deprivation On Histopathological Changes And Oxidative Damage In Different Type Muscle Fibers: 2145 Board #301 May 30 3:30 PM - 5:00 PM

Previous studies has shown that sleep deprivation (SD) induces muscle atrophy and histopathological changes, however, these effects may be different considering the type muscle fiber. PURPOSE: to analyze histopathological changes and oxidative damage after SD in different types of muscle fibers (oxidative and glycolytic) of rats. METHODS: 20 Wistar male rats (3 months, 300-350 g) were distributed in two groups, control group (CTL, n=10) and SD by 96 h group (SD96, n=10). The SD96 group was sleep deprived on consecutive 96 h, while the CTL group remained in the housing box. At the end of SD, the soleus and plantar muscles were analyzed for lipid peroxidation by concentrations of malondialdehyde (MDA), oxidative damage to DNA by nuclear labeling of 8-OHdG and histopathological changes. RESULTS: it was observed increased MDA concentrations in the soleus of SD96 compared to CTL (0.0134±0.0009 vs 0.0121±0.0009 mmol/mg, P=0.01). Comparison between muscles revealed that the soleus had higher concentrations of MDA than plantar to both groups (P<0.001 for both). Regarding 8-OHdG, there was increased nuclear labeling to the plantar muscle in the SD96 compared to CTL (25.4±3.6 vs 7.2±1.9 positive cells, P<0.001). In the soleus, greater nuclear labeling was observed in SD96 compared to CTL (60±13.6 vs 9.6±3.6 positive cells, P<0.001), already the comparison between the muscles revealed a greater nuclear labeling of 8-OHdG in the soleus muscle compared to plantar in the SD96 group (P<0.001). The histopathological evaluation of the soleus revealed the presence of interstitial edema in SD96 compared to CTL (19.5±4.2% vs 0%, P<0,001), associated with intense cellular infiltration, alterations in the arrangement of muscle fibers, as well as areas of tissue degeneration and reduction of muscle parenchyma (72,7±2,7 vs 92,4±1,6%, P<0,01). In the plantar muscle, the changes were more subtle, with slight increase in cellularity in the SD96 and fibers presenting smaller cross-sectional area in SD96 group. CONCLUSIONS: SD induces degenerative process and oxidative damage in the skeletal muscle, being more intense in type I fibers.