ABSTRACT
Objective To discuss the effect of the electric stimulation on the free radicals and Nrf2 signaling pathway in skeletal muscle myoblasts(C2C12) of mice.Methods After 6 days of differentiation,skeletal muscle myoblasts(C2C12) cells of mice were randomly divided into a control group and an electrical stimulation group.The control group was not stimulated,while the electrical group was stimulated 30,45,60,75,90,120 and 150 minutes respectively with the electrical parameter as 20 ms,45 V and 5 Hz.The reactive oxygen species(ROS),glutathione peroxidase(GSH-Px) and nuclear factor E2 related factor 2(Nrf2) protein expression in C2C12 muscle tubes were determined.Results Compared with the control group,the amount of ROS produced in the C2C12 muscle tube increased significantly in the stimulation group(P＜0.05),except those stimulated for 30 and 150 minutes,with greatest increase for those stimulated for 60 and 120 minutes(P＜0.01).Compared with the control group,the activity of GSH-Px and the expression of Nrf2 nuclear protein increased significantly in all the stimula tion group(P＜0.05),except those stimulated for 30 minutes and with the greatest increase for those stimulated for 75 and 150 minutes(P＜0.01).Conclusion The electrical stimulation of 45 V,20 ms and 5 Hz can cause oxidative stress in the C2C12 muscle tube.Based on the variation of ROS production with the time of electric stimulation,it is found that only when ROS increases to a certain amount,can it activate the Nrf2 signaling system and related genes to make the GSH-Px play an antioxidant role.However,with the increase of stimulation time,the anti-oxidative ability decreases slightly,and then it continues to maintain its high level.
ABSTRACT
BACKGROUND:Autologous micro-skin graft covered with alogeneic skin has become a major means for repair of extremely severe burn wounds. Due to the limitation of the source of alogeneic skin, heterogeneous skin (pigskin) or artificial skin serves as a vector to cover the wound on the clinical use. OBJECTIVE: To observe the curative effect of thin-thickness micro-skin pulping covered with heterogeneous skin for repair of burn wounds in comparison with blade-thickness micro-skin pulping covered with heterogeneous skin. METHODS:A self-control study was performed in 36 patients with severe burns of bilateral limbs. There were 42 pairs of wounds, 32 of which were at joint sites. One or two pairs of III-degree burns treated with escharectomy were selected from each patient for self-control comparison. Covered with heterogeneous skin, thin-thickness micro-skin pulping and blade-thickness micro-skin pulping were used in the trial and control groups, respectively. The expansion ratio was controled at 1:8-1:12 in al patients. Wound healing time, degree of scar hyperplasia within 6 months to 2 years after transplantation, and ratio of reconstruction surgery at joint sites were observed and compared. The removed scars by surgery were analyzed based on the total score of the Vancouver Scar Scale. RESULTS AND CONCLUSION: The average wound healing time was (44.7±1.24) days in the trial group and (49.6±1.41) days in the control group, and there was a significant difference between the two groups (P 0.05). The reconstructive surgery ratio of the trial group was 38%, significantly lower than that of the control group (59.38%;P < 0.01). The total score on the Vancouver Scar Scale was less in the trial group than the control group (P < 0.05). These findings suggest that the thin-thickness micro-skin covered with heterogeneous skin is likely to be a better treatment to repair large ful-thickness skin burn by increasing the thickness of micro-skin, and it can obtain better wound healing quality.