| Objective:To study the effects and mechanisms of Nuclei factor E2-related factor 2(Nrf-2)and Heme oxygenase 1(HO-1)in regeneration of skeletal muscle and to explore the relationship between the changes of their expression and the wound age.Methods:Sprague Dawley male rats,10~12-weeks old,were used in present study.The staged skeletal muscle degeneration was induced by injecting cardiotoxin into gastrocnemius muscle,then impairment muscle samples were harvested at each time point(0h?1h ?4h?8h?12h?16h?1d?3d?5d?7d?9d?13d?17d?21d after injury).The degree of muscle damage and regeneration were evaluated by H&E staining on muscle sections.The variation of reactive oxygen species(ROS)in injured tissues was detected by DCFH-DA.The expressions of Nrf-2 and HO-1 in repair process of skeletal muscle were investigated by immunofluorescence stain and Western blotting,and the m RNA of Nrf-2 was detected by Quantitative Real-time PCR.Results:Atfer the skeletal muscle injuried,necrosis tissue was infiltrated successively by neutrophils and mononuclei cells.There is a large number of immature muscle cells at the5 th day,and nature myotube at the 21 st day.Comparing with the control group,the results showed that ROS increases and decreases rapidly in the 1st hour,and Nrf-2 mRNA and proteins in cells of injured tissue only rised in a few groups.Moreover,Nrf-2 proteins innucleus were significantly increased as early as 1 hour after injury,reached the peak at 1st day,then returned to the initial level at 17 th day post-injury.Similarly,HO-1 proteins increased rapidly after injury,reached the peak at the 1st to 3rd day,and gradually recovered in the later stage.There is a relation of positive linear correlation in the expression of Nrf-2 protein in nucleus and HO-1 protein,and they all change along with the wound age.Conclusions:1.It is demonstrated that oxidative stress signal pathway takes part in the regeneration of the repair process of rat skeletal muscle after injury.The Nrf-2 and HO-1 protein promote the recovery of the structure and function of injuried skeletal muscle by inhibiting the inflammatory reaction,activating and inducing the proliferation and differentiation of the muscle satellite cells.2.In the repair process of rat skeletal muscle after CTX damaged,the content of the Nrf-2 protein in the nucleus,in which Nrf-2 can play its biological role,were increased mainly by translocation from the cytoplasm.3.In the repair process of rat skeletal muscle,the expression of Nrf-2 and HO-1 were changed with the injury time.The relation of them could be used as the new index of wound age. |
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