Effects of transcutaneous electrical acupoint stimulation on mitochondrial quality control during endotoxin-induced acute lung injury in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of transcutaneous electrical acupoint stimulation (TEAS) on mitochondrial quality control during endotoxin-induced acute lung injury (ALI) in mice.Methods:Twenty-four clean-grade healthy male C57BL/6J mice, aged 4-6 weeks, weighing 15-20 g, were divided into 4 groups ( n=6 each) according to the random number table method: control group (group C), endotoxin-induced ALI group (group L-ALI), endotoxin-induced ALI plus acupoint electroacupuncture group (group L-ALI+ EA), and endotoxin-induced ALI plus non-acupoint electroacupuncture group (group L-ALI+ SEA). Lipopolysaccharide (LPS) 15 mg/kg was injected via the caudal vein to develop the model of endotoxin-induced ALI in anesthetized mice.In group L-ALI+ EA, at 5 days before LPS injection, bilateral Zusanli and Feishu acupoints were stimulated with an electric stimulator for 30 min each time at a voltage of 1-2 mA and a frequency of 2/15 Hz until the end of the experiment.In group L-ALI+ SEA, stimulation was performed at the points 0.5 cm lateral to the acupoints of bilateral Zusanli and Feishu non-meridian and non-acupoint sites using the shallow puncture method, and the other treatment methods were the same as those previously described in group EA.Group C received no treatment.The mice were sacrificed by euthanasia at 12 h after LPS administration, and lung tissues were obtained for microscopic examination of the pathological changes (with a light microscope) and structure and morphology of mitochondria (with a transmission electron microscope) and for determination of the levels of reactive oxygen species (ROS) and mitochondrial DNA (mtDNA) and contents of glutathione (GSH) and glutathione oxidized (GSSG). The GSH/GSSG ratio was calculated.The expression of mitochondrial fusion proteins mitofusin 1 (Mfn1), Mfn2, optic atrophy1 (OPA1), dynamin-related protein 1 (Drp1), fission protein 1 (Fis1), peroxisome-proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor-1 (NRF1), NRF2, PTEN-induced putative protein kinase 1 (PINK1) and the E3 ubiquitin ligase (Parkin) was determined by Western blot. Results:Compared with group C, the level of ROS and contents of GSSG and mtDNA were significantly increased, GSH content and GSH/GSSG ratio were decreased, the expression of Mfn1, Mfn2, OPA1, NRF1, NRF2 and PGC-1α was down-regulated, and the expression of Drp1, Fis1, PINK1 and Parkin was up-regulated in L-ALI, L-ALI+ EA and L-ALI+ SEA groups ( P<0.05). Compared with group L-ALI, the level of ROS and contents of GSSG and mtDNA were significantly decreased, GSH content and GSH/GSSG ratio were increased, the expression of Mfn1, Mfn2, OPA1, NRF1, NRF2 and PGC-1α was up-regulated, and the expression of Drp1, Fis1, PINK1 and Parkin was down-regulated in group L-ALI+ EA ( P<0.05). Compared with group L-ALI+ EA, the level of ROS and contents of GSSG and mtDNA were significantly increased, GSH content and GSH/GSSG ratio were decreased, the expression of Mfn1, Mfn2, OPA1, NRF1, NRF2 and PGC-1α was down-regulated, and the expression of Drp1, Fis1, PINK1 and Parkin was up-regulated in group L-ALI+ SEA ( P<0.05). Conclusions:TEAS can reduce endotoxin-induced ALI probably through regulating mitochondrial quality control in mice.