Cigarette Smoking Induced Skeletal Muscle Inflammation In Mice

Objetive Cigarette smokeing exposure can induce lung abnormal inflammatory response leading to emphysema, it also can cause inflammation of other parts of the body, this research focus on the effect of tobacco smoke on skeletal muscle.Methods48male Kunming species mice were randomly divided into four groups (n=12):12weeks of normal control group (group A),12weeks of smoke exposure group (group C);24weeks the normal control group (group B),24weeks of smoke exposure group (group D). By the simple long-term passive inhalation of cigarette smoke to establish the experimental model. Then observe:(1) The gross morphological changes of mice:the anatomy of the lungs generally pathological changes; weighing the body weight of mice before and after smoke exposure.(2) The changes of the skeletal muscle of mice:①observe the morphological change of the lung tissue and skeletal muscle②Detect cytoplasmic myosin heavy chain isoform Ⅱ beta chain of skeletal muscle by Western blot. (3) Observe the level of the interleukin-8and tumor necrosis factor-a in skeletal muscle with Enzyme-linked immunosorbent assay.(4) The expression of the inflammatory gene expression in skeletal muscle. Detect the histone deacetylase enzymes2protein expression with Western blot and HDAC2mRNA expression with reverse transcriptase-polymerase chain reaction②Explore the nuclear factor-κB/P65protein expression.By Western blot.Results (1) Watch general situation, C, D group contrast of A and B group of mice, the smoke exposure group are appear hair sparse, dull, part of the vertical hair. Smoking after12weeks, C, D group of mice low weight, compared with A and B group (P<0.05), A statistically significant difference;Smoking after24weeks, the group D mice with group B compared smoke exposure group weight is significantly lower. Dissection observation in the lungs pathological form found:smoke exposure group than normal lung volume of swollen, edge obtuse, more than the visible surface size differ big bubble, lungs retraction was poor.(2) The observation of cigarette smoke exposure in mouse lung tissue biopsy found:expansion of the alveolar space, part of the alveolar septum fracture, fusion of the alveolar space, lung tissue bulla formation with peripheral inflammatory cell infiltration, indicating that the formation of emphysema model. Further observed that mouse skeletal muscle tissue biopsy found:smoke exposed group in muscle tissue, inflammatory cell infiltration accompanied by muscle morphological changes, disorganized, localized necrotic lesions produce, indicating that the model of emphysema in mice skeletal muscle inflammation created. Detected by Western blot A, B, C and D mice skeletal muscle expression of MHC-Ⅱβ chain.protein, respectively, as follows:1.2103±0.2197,1.1782±0.2046,1.1151±0.1956,0.6775±0.1645, the normal control group (A,B),12weeks smoke exposure group (C) and24weeks of smoke exposure group (D) between the expression of a statistically significant difference (P<0.05), lower MHC-II (3chain protein expression levels in the smoke exposed groupin the normal control group.(3) Detected by ELISA in group B and group D of skeletal muscle homogenate (supernatant) in the average concentration of IL-8:195.49and233.88, the IL-8concentration in the smoke exposed group than in normal control group; Detection of inflammatory factors TNF-a in the average concentration of124.6651and150.7417,or TNF-a concentration of smoke exposure group than in the normal group.(4) RT-PCR assay B, D, HDAC2mRNA expression levels by measuring CT values calculated using Paffl method:smoke exposed group/normal control group (the Median)=0.64, confirmed that the mRNA expression levels of HDAC2in the smoke exposed group is lower than the normal control group.。Detected by Western blot A, B, C, D mice skeletal muscle tissue HDAC2expression levels, respectively,0.5942±0.1078,0.5366±0.2179,0.2978±0.1135,0.2290±0.0772, expression of the normal control group (A, B) expression compared smoke exposure group (C and D), the difference was statistically significant (p=0.000), HDAC2in the smoke exposed group was significantly lower than the normal control group;Detection NF-κB/P65protein expression, respectively, as follows:0.4901■0.2591,0.5166±0.2319,0.5263±0.2448,1.1230±.3725, normal control group (A, B),12weeks of smoke exposure group and24weeks of smoke exposure group expression difference was statistically significant (P<0.05), of NF-κB/P65protein in the smoke exposed group is higher than the normal control group;Detection of MHC-Ⅱβ chain protein expression levels were:1.2103±0.2197,1.1782±0.2046,1.1151±0.1956,0.6775±0.1645, the normal control group (A, B),12weeks of smoke exposure group (C) and24weeks of smoke exposure group(D) between the expression of a statistically significant difference (P<0.05), MHC-Ⅱβ chain protein expression in the smoke exposure group is lower than the normal control group.Conclusion1、The long-term tobacco smoke exposure can result in mouse skeletal muscle cell vacuolar degeneration, atrophy and dissolution of MHC-Ⅱβ chain protein content in the muscle fibers display can lead to changes in skeletal muscle structure and function2、The long-term tobacco smoke exposure can lead to skeletal muscle inflammatory factors (IL-8, TNF-alpha) and inflammatory regulation of gene NF-κB activity was significantly enhanced, HDAC2expression was significantly reduced skeletal muscle show a significant inflammatory response.