Studies On The Repair Mechanism Of Hunan Dark Tea For Cigarette Smoke Exposure Inducing Oxidative Stress Injury In Mice Lung

Cigarette smoke (CS) is inhaled into the lungs, through oxidative stress, inflammatory reaction, and varieties in gene expression levels and other metabolic pathways leading to oxidative stress injury. It has not been reported that dark tea can improve lung oxidative stress relieve induced by CS exposure. In this study, C57BL/6 mice were put into CS exposure box which was made by ourselves for 9 weeks for CS exposure to establish CS induced lung oxidative stress injury model, then the CS exposure model mice were treated with oral administration 20mg/kg EGCG,200mg/kg and 1000mg/kg water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea for 4 weeks. Detection quality of life in each treatment groups, pathological sections of lung tissue; oxidation indexes in serum, inflammatory factors in lung tissue; relative expressions levels of Bcl-2, Bax, Jak2 and Stat3 gene mRNA in lung tissue, to explore the repair mechanism of dark tea for cigarette smoke exposure inducing oxidative stress injury in C57BL/6 mice lung.The experimental results showed that:(1) Qualities of C57BL/6 mice lives were significantly improved. C57BL/6 mice lung oxidative stress reaction induced by CS exposure, compared with the normal control group, the food intakes decreased, body weight increase rates slow; oral administration 20 mg/kg of EGCG,200mg/kg and 1000 mg/kg water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea, these groups survival qualities and mental states were improved, food intake increased, body weight increased even closed to the normal mice levels which compared with CS exposure group.(2) Lung pathological sections in C57BL/6 mice were significantly variation. After CS exposure, alveolar septum in C57BL/6 mice were thicken, alveolar shape changed, spacing increased, the alveolar capillary congestion expanded, bronchial ciliated fuzzy or even disappeared, endotracheal microvascular bleed, many neutrophil graneulocytes and macrophagocytes were infiltrated to part of the alveolar cavities, inflammation of lung tissue were serious. Comparing with CS exposure model groups, oral administration 20mg/kg EGCG,200mg/kg and 1000mg/kg water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea, the lung alveolar appeared regular shapes, alveolar vascular dilation and congestion phenomenon were relieved, bronchial mucosa parts were integrated, cilia distribution were clear and even, a small amount of lymphocytic infiltration to lung pulmonary alveoli. Oral administration 200mg/kg water extractions of Primary Dark Tea, 1000mg/kg water extractions of Fu Brick Tea and Qian Liang Tea, and 20mg/kg EGCG achieved good repairing results. (3) The indexes of oxidative stress inflammatory in serum of C57BL/6 mice were significantly variation. Comparing with the normal control group, contents of MDA GSH-Px, MPO in CS exposure group decreased significantly (P?0.01), the content of T-SOD increased significantly (P?0.01); Oral administration 20mg/kg EGCG,200mg/kg and 1000mg/kg water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea, the levels of MDA, GSH-Px, MPO and T-SOD in serum were significant difference (P?0.05) which compared with CS model group; Oral administration 20mg/kg EGCG 200mg/kg and 1000mg/kg water extractions of Primary Dark Tea, 1000mg/kg water extractions of Qian Liang Tea, the content of MDA in serum of mice recovered to the normal levels (66.64 ± 4.01 nmol/mL); Oral administration 20mg/kg EGCG,200mg/kg and 1000mg/kg water extractions of Primary Dark Tea,200mg/kg water extractions of Fu Brick Tea, 1000mg/kg water extractions of Qian Liang Tea, the contents of GSH-Px in serum of mice recovered to the normal levels (1800 ± 10.91 U/mL); Oral administration 20mg/kg EGCG 200mg/kg, 1000mg/kg water extractions of Primary Dark Tea and 200mg/kg water extractions of Fu Brick Tea, the contents of MPO in serum of mice recovered to the normal levels (116.59+7.30 U/L).(4) The inflammatory factors in lung tissue of C57BL/6 mice were significantly changed. Contents of TNF-a, ROS and IL-8 in lung tissue was significantly increased in CS model group(P<0.01); Oral administration 20mg/kg EGCG,200mg/kg water extractions of Primary Dark Tea and 1000mg/kg water extractions of Fu Brick Tea, TNF-? in lung tissues of mice were significant decreased compared with the CS model group (448.90 ± 17.75 ng/g) (P<0.05); the contents of ROS in all tea treatment groups were significant decreased(P<0.05) compared with the CS model group (12817.63+ 247.95 AU/mg prot); Oral administration 200mg/kg and 1000mg/kg water extractions of Primary Dark Tea,200mg/kg water extractions of Qian Liang Tea, contents of ROS recovered to normal levels (3284.57 +219 AU/mg prot); Oral administration 20mg/kg EGCG, 1000mg/kg water extractions of Fu Brick Tea, contents of IL-8 in lung tissue were recovered to the control group levels (95.23+3.06 pg/g).(5) There were significant changes in JAK2/STAT3 inflammatory metabolic pathway for C57BL/6 mice in lung tissue. After CS exposure, comparing with normal control group, Bcl-2 mRNA expression levels in lung tissue were down-regulated, Bax, JAK2 and STAT3 mRNA expression levels in lung tissue were up-regulated (P< 0.05); Compared with the model of CS exposure group, oral administration 20mg/kg EGCG,200mg/kg and 1000 mg/kg water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea, bcl-2 mRNA expression levels in lung tissue were up-regulated, Bax, JAK2 and STAT3 mRNA expression levels in lung tissue were down-regulated and recovered to the normal control group levels.Therefore, the CS exposure can lead to oxidative stress injury for C57BL/6 mice in lung tissue. Oral administration EGCG, water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea, can made food intake increased, the weight of mice recovered to the normal levels; relieved the deformation of the alveolar and vascular dilatation and congestion phenomenon, made bronchial ciliated distribution clearly and evenly, reduced infiltration of inflammatory cells; repaired oxidative indexes in mice serum; decreased the contents of TNF-?, ROS, IL-8 in lung tissue; regulated Bcl-2, Bax, JAK2 and STAT3 mRNA relative expression levels in mice lung tissue. Therefore, EGCG and water extractions of Primary Dark Tea, Fu Brick Tea, and Qian Liang Tea had obviously repair roles on oxidative stress injury in lung tissue for C57BL/6 mice after CS exposure.