Critical Illness Myopathy Study The Expression Of Autophagy-related Factor MTOR, Beclin1, LC3 In Rat Skeletal Muscle

PurposeObservation of dexamethasone on rat critical illness myopathy(CIM) in skeletal muscle autophagy and autophagy-related factor m TOR, Beclin1, LC3 expression, explore dexamethasone-induced critical illness myopathy possible mechanism.MethodsSPF SD male rats were 40, one week after feeding adaptation, were randomly divided into four groups of 10. Groups as follows: control group, 7d experimental group, 9d experimental group, 11 d experimental group. The experimental group 5mg / kg dexamethasone intraperitoneal injection once a day in the control group were injected with saline. Using muscle function impairment score and footprinting judgment muscle impairment situation. By immunohistochemistry and Western blot to detect the expression of autophagy-related factors in skeletal muscle m TOR, Beclin1, LC3 in.ResultsThe control group had no symptoms of muscle function defects, while the experimental group showed varying degrees of functional impairment of muscle symptoms in the 7d experimental group part muscle impairment symptoms, the 9d, 11 d experimental group all significant impairment of muscle symptoms, the most serious degree of defects in rats at the 11 d experimental group. Immunohistochemistry: the control group showed normal muscle fibers in skeletal muscle structure, the experimental group showed different degrees of pathological changes in muscle fiber atrophy. Control group can be seen visible m TOR positive granules in the experimental group of muscle fibers in the cytoplasm with time m TOR expression decreased cell; the control group or a small amount of visible Beclin1, LC3 positive granules, the cytoplasm of the muscle fibers in the experimental group showed obvious Beclin1, LC3 expression to the point when the 11 d experimental group with the most obvious expression. Western blot detection : group can be seen m TOR expression faint bands, with time, m TOR positive bands gradually reduced; the control group can be seen weak Beclin1, LC3 expression bands, the experimental group of muscle fibers in the cytoplasm can be seen clearly the positive bands of Beclin1, LC3, when expressed relative to the most obvious point 11 d experimental group.ConclusionIntraperitoneal injection of a large dose of dexamethasone can induce the critical illness myopathy, dexamethasone-induced CIM may inhibit m TOR, activate Beclin1, LC3 expression of which play a regulatory role for autophagy.