Pathological Changes Of A Simulated Dry Eye Model Induced By Tobacco Smoke In Mice

Objective:To explore the pathological changes of tobacco smoke induced dry eye model in mice.method:Eighteen male C57 BL mice(18-22g)without specific pathogen were selected.Six of them were treated with tobacco smoke for 4 weeks and 6 with tobacco smoke for 12 weeks.According to the design of 20 cigarettes per day,tobacco smoke poisoning was carried out.Mice were placed in the poisoning cabinet,and smoke was transferred 3 times per day(30 minutes / time).The mice were randomly divided into control group,4-week group and 12-week group.The time of tear break(but)test,in vivo staining,inflammatory index score,fluorescein staining and confocal microscopy were performed in each group.At the 4th and 12 th week of euthanasia,Western blot,immunofluorescence,TUNEL,PAS and he staining were performed on the eyes of euthanized mice.Result:There was no difference in the scores of BUTs,FL score and confocal microscopy among the three groups before intervention.After intervention,compared with the other two groups,the BUTs decreased,FL score increased significantly,corneal epithelial cell density decreased,basal epithelial cell density increased,corneal epithelial and conjunctival thickness of 12-week group decreased significantly,increased.The difference was statistically significant(P < 0.05).The results of sodium fluorescein staining and confocal microscopy were negative in the control group and 4-weeks group,and HE staining did not change significantly.The 12-week group was positive.In the 12-week group,the corneal epithelial cells showed necrosis and exfoliation,strong reflection,enlarged cell gap,and sparse defect arrangement of basal epithelial cells.In the 12-week group,the corneal epithelial cells were disordered,local defect and exfoliation of superficial epithelial cells,unsmooth surface,proliferation and thickening of conjunctival epithelial cells,a small amount of nuclear shrinkage and nuclear disappearance.There were more Pas staining,mucin immunofluorescence staining,tunenl staining,Ki67 staining and 8-OHdG positive cells in the 12 week group than in the other two groups(P < 0.05).In the 12 week group,there were more microvilli and fewer desmosomes than in the other two groups(P < 0.05).Conclusion:Tobacco smoke is not only the source of free radicals,but also destroys the endogenous antioxidant system,leading to apoptosis and inflammation.Enough time and concentration of tobacco smoke will lead to tear film damage,change the structure of the eye surface and lead to dry eye.