Abstract:

Objective　To investigate the expression of critical illness myopathy on autophagy-related factors p62 and ubiquitin in rat skeletal muscle.　Method　SD rats were divided into control and experimental groups; Experimental groups were divided into groups of 7, 9, 11d time points （n=10. Rats in experimental groups recerved intraperitoneal injection of dexamethasone 5 mg/kg once daily, and the healthy control group received intraperitoneal injection of normal saline. Muscle function were determined by muscle function impairment score. By immunohistochemistry and Western blot analysis the expression of skeletal muscle autophagy-related factors p62 and ubiquitin were determined.　Results　Compared with rats in the control group, rats in the experimental group demonstrated a varying degrees of muscle function impairment symptoms, with impairment most serious in rats in 11d point group. Immunohistochemistry showed visible expression of ubiquitin-positive cells and no p62-positive cells in a small group of skeletal muscle fibers. In the experimental group, a small amount of p62 and ubiquitin were expressed in the muscle fibers; the expression of p62 and ubiquitin was reduced the most obviously at 11d point. Western blot confirmed the same trend.　Conclusion　p62 and ubiquitin may play an important role in cell autophagy of skeletal muscle in critical illness myopathy in rats.

Key words: Dexamethasone, Critical illness myopathy, p62, Ubiquitin