The Experimental Study On The Effect Of PM₁₀ On Tear Film Function And Ocular Surface Structure Of Balb/c Mice

Objective:To explored the effects of particulate matter 10(PM₁₀)eye drops on ocular surface structure and tear function in mice.Methods:Totally 60 male Balb/c mice were divided into two groups:group A(PBS eye drops,n=30 and group B(PM₁₀ eye drop group,n=30).Four times a day,every time 5ul with the concentration of 5.0 mg/ml PM₁₀,for 14 consecutive days in right eye.The clinical indications of dry eye were evaluated including tear break-up（BUT）,tear volume,corneal fluorescein staining,rose bengal staining,Lissamine Green staining and inflammatory index before therapy and 0 day,4 days,7 days and 14days after droppings,respectively.Global specimens were collected on D14 and the following examinations were performed histologic investigation by light microscopy,Hematoxyin-eosinstaining,Periodic acid-schiff,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.immunnostaining of cytokeration 10（K10）in cornea,and Western Blot analysis of tumor necrosis factor-α（TNF-α）,NF-ΚB p65 and p-NF-ΚB p65 to assess the effects of PM₁₀ on Balb/c mice ocular surface.Results:In 0d、4d、7d and 14d,after treatment with PBS and PM₁₀,there were no statistical changes in tear volume、BUT and fluorescein staining（P>0.05）in group A.For group B,there were statistical differences in all items at each time point（P<0.05）.In 14d after therapy,in group B,the tear secretion decreased and break-up time shortened,The score of FL,rose bengal staining and Lissamine Green staining in group B is also higher than that in group A（P<0.05）.HE staining showed that the mean layer of corneal epithelial cells in the group A was significantly lower than that in the group B（P<0.05）.PAS staining showed that the number of goblet cells in the conjunctival fornix of group B was significantly lower than that in the group A.Apoptosis experiments showed apoptosis of corneal superficial and basal epithelium in group B.High expression of K10 in B group was detected by immunofluorescence,indicating that PM₁₀ could lead to abnormal differentiation and proliferation of ocular surface epithelium.The results of WB experiment showed that the expression of TNF-a,NF-ΚB p65 and p-NF-ΚB p65 in group B increased significantly.Scanning electron microscopy and transmission electron microscopy showed that the number of corneal epithelial microvilli and corneal desmosomes in group was lower than that in group A.Conclusion:PM ₁₀ can damage the tear film function and cause the destruction of the organizational structure of ocular surface in mice.Topical administration of PM₁₀ in mouse induces ocular surface changes resembling those of dry eye in humans.