Diesel Exhaust Particles Exposure Damage The Ocular Surface In Mouse

Purpose:To explore the effects of diesel exhaust particles(DEP)eye drops on ocular surface structure in mice,and to find a novel animal model for environmental eye disease researchMethods:A total of 40 male C57BL/6J mice were used in this study and divided into four groups:blank control group(no treatment,n=4),control group(0.9%saline eye drops,n = 12),low concentration group(100μg/ml eye drops,n = 12)and high concentration group(1000μg/ml DEP eye drop group,n = 12).Topical administration was given twice times a day,5ul,each time for 28 consecutive days in eyes.Corneal staining was measured before and after therapy on D0,14 and 28,respectively.Eye samples were collected on D0,14 and 28 and examined by histologic light microscopy,TUNEL assay,Ki67,caspase-3 and 8 immunostaining,CD4 immunohistochemical staining and NF-κB p65(phospho S536)western blot analysis.DEP was examined by scanning electron microscope(SEM)and inductively coupled plasma mass spectrometry(ICP-MS)measurementResults:SEM examinations indicated that particles have porous structure which can adsorb many ingredients,both organic and inorganic matter,which was detected by ICP-MS.At 14d and 28d after treatment with or without saline,there were no statistical changes in ocular surface staining(P>0.05).For groups treated with high concentration of DEP,all indices showed statistical differences at each time point(P<0,05).The average number of corneal epithelial cells layer in high concentration group was significantly more than that in control group(P<0.05).DEP induced apoptosis in the corneal and conjunctival epithelium,and leaded to abnormal differentiation and proliferation of the ocular surface with higher expression levels of Ki67 and reduced the number of goblet cells in the conjunctival fornix.DEP significantly increased the number of CD4 positive cells in conjunctiva and the levels of NF-κB p65(phospho S536)in both cornea and conjunctival.Conclusion:DEP cause the destruction of the organized structure of ocular surface and induce the inflammation of cornea and conjunctiva in mice.