Effects of PM2.s on tear film function and corneal epithelial structure in mice / 眼科新进展

ABSTRACT

Objective To investigate the effects of PM2.5 on tear film function and corneal epithelial structure in mice.Methods Totally 24 male BALB/c mice (24 eyes) were divided into two groups:group A (with PBS eye drops,n =12),group B (5 mg · mL-1 PM2.5 eye drop group,n =12).PBS and PM2.5 eye drop were given with four times per day for 7 consecutive days in right eye.Tear secretion level was measured with phenol red thread.Break-up time (BUT) of tear film was tested,and corneal fluorescein staining (FL) was scored before therapy and 1 day,4 days and 7 days after droppings and HE staining was performed 7 days after droppings,respectively.Results There was no significant difference in the tear secretion levels,BUT,FL between the groups A and B before treatment (all P ＞ 0.05).At 4 days,7 days after treatment with PM2.5,the mean differences of the group B showed all items significantly changed compared with those before treatment (all P ＜ 0.05).For the group A,there was no statistical change in tear secretion levels,BUT,FL at 7 days after treatment (all P ＞ 0.05).There were statistical differences in all items between group A and B at each time point (all P ＜ 0.05).At 7 days after therapy,the mean layers of corneal epithelial cells in the group A (4 ± 1) was significantly lower than that in the group B (7 ±l) (P ＜0.05).The group B showed that the whole corneal fluorescein staining obviously increased,and corneal epithelial cell layer was thickened.Conclusion PM2.5 can influence tears film function and damage the corneal epithelial structure in mice.