ABSTRACT
Aim To explore whether histone modifications are involved in the process of uterine injury alleviated by TSA in female mice induced by cigarette smoke (CS) exposure. Methods Female mice were exposed to CS twice daily for 30 days and TSA was injected intraperitoneally into CS-exposed mice on alternate days in the TSA-treated group. HE staining was used to observe the morphological changes of mice uterus after CS exposure; Western blot was used to assess the global modification levels of H3K4mel, H3K4me2, H3K4me3, H3K9mel, H3K9me2, H3K9me3 and H3K27me3 in uteri. GLP (H3K9 his-tone methyltransferase) , G9a (H3K9 histone methyl- transferase) , EZH2 (H3K27me3 histone methyltrans ferase ). Results TSA effectively restored the number of glandular and interstitial cells reduced by CS exposure. Western blot results showed that TSA significantly inhibited global H3K9mel modification and further aggravated H3K27me3 change induced by CS exposure. Furthermore TSA suppressed GLP and G9n expression in mouse uterine tissue induced by CS exposure, but further activated EZH2 increase. Conclusions Histone modifications are involved in the process of uterine injury alleviated by TSA in female mice induced by cigarette smoke exposure.
ABSTRACT
In recent years, with the rapid increase of smoking in the world, male reproductive toxicity induced by cigarette smoking (CS) has attracted increasing attention. Studies have shown that long-term heavy smoking can lead to testicular damage in men, resulting in decreased semen quality, but the specific mechanism is still unknown. This study aimed to investigate the regulation mechanism of the Bcl-2 signaling pathway in rat testicular apoptosis induced by CS exposure. SPF male SD rats were randomly divided into high, medium and low CS exposure groups (30, 20 and 10 non-filtered cigarettes/ day, respectively) and control groups. The rats in each group were treated with static exposure methods and were anesthetized after 2, 4, 6, 8 and 12 weeks-CS exposure, respectively. The testicular organ coefficient was calculated, and the testicular histopathological changes and apoptosis in rats were detected. The mRNA and protein expressions of Apaf-1, Caspase-9, Bim, Bcl-w and Bak in the mitochondrial apoptosis pathway were detected. Results indicated that with the increase of exposure dose and duration, the weight of rats in exposure groups gradually decreased, the testis in exposure groups showed obvious pathological changes, and the testicular organ coefficient gradually decreased. Compared with the control groups, the testicular organ coefficient in the middle, high-dose groups at the 8th week and all groups at the 12th week significantly decreased (P 0. 05). In conclusion, long-term heavy smoking activated the mitochondrial apoptosis pathway and induced testicular irreversible apoptotic damage. These results provide a scientific basis for further study of the molecular mechanism of male reproductive injury induced by cigarette smoking.
ABSTRACT
Objective To explore the in vivo exposure levels of cigarette smoking ( CS) by measuring the biomar-kers nicotine and cotinine. Methods One hundred and sixty male SD rats were divided into 15 cigarette exposure groups (10, 20 and 30 nonfilter cigarettes/day, for 2, 4, 6, 8 and 12 weeks) and a control group (without CS exposure). The rats were sacrificed at different time?points. The concentration of plasma nicotine and cotinine were measured by GC?MS/MS. Results The CS?exposed rats displayed decreased locomotor activity, ataxic gait, irregular respiration, nasal noise, and salivation after smoking exposure for 3 weeks. Rats in the CS exposure groups had lower body weight, and the reduction of body weight was time and dose related (P<0. 01). The retention time of nicotine was 7. 5 to 8. 5 min. The concentra?tion of plasma nicotine in the CS exposure groups was higher than control group (155 ± 56. 65) ng/mL. The retention time of cotinine was 11. 5 to 12. 5 min, the concentrations of plasma cotinine in CS exposure groups were higher than control group (340 ± 41. 97) ng/mL, the increase of plasma cotinine in CS groups was time?related (P<0. 05), and the exposure concentration and duration had synergistic effect on the level of plasma cotinine ( P<0. 05 ) . Conclusions CS exposurecauses structural damages in male rats. The plasma concentration of cotinine can effectively reflect the in vivo exposure lev?els of cigarette smoking, and well presents a dose?response relationship.
ABSTRACT
Objective To observe the changes of pulmonary oxidative stress after cigarette smoking exposure,its re-lationship with inflammatory cytokines,and the effects of smoking cessation. Methods Fifty male BALB / c mice were randomly divided into the smoke exposure group,smoke cessation group,and the controls. Mice in smoke cessation group were exposed to cigarette smoking for 16 weeks. On 4,8,and 12 week after smoking cessation mice were executed and the bronchoalveolar lavage fluid(BALF)and lung tissue were collected. The morphologi-cal alternations of lung tissue were observed. Mean length of interval and mean alveolar number were measured. Total cell numbers in BALF were counted. Superoxide dismutase(SOD)activity was measured with hydroxylamine method,malondialdehyde(MDA)level was measured with TBA method. The levels of pulmonary interleukin-8 (IL-8)and tumor necrosis factor-α(TNF-α)in BALF and lung tissue homogenate were measured with ELISA. Re-sults Compared with the mice in the controls,emphysematous changes were remarkable in the lung of cigarette ex-posed mice,the total cell numbers in BALF were increased significantly(P < 0. 05)and reduced gradually after smoking cessation(P < 0. 05). SOD and MDA levels increased remarkably in the cigarette exposure group(P <0. 05),and declined gradually after smoking cessation. The levels of IL-8 and TNF-α in BALF and lung tissue ho-mogenate in the smoke exposure group increased significantly( P < 0. 05),and lowered time-dependently after smoking cessation,but not reached to normal level even 12 weeks after smoking cessation. SOD and MDA levels were positively correlated with the cytokine changes. Conclusion Abnormal oxidative stress in the airways caused by cigarette smoking exposure was merely partially reversed after smoking cessation. And the inflammation remains persistent concomitantly.