2022 Annual Meeting and Alumni Reunion
Category : Basic and Translational Research Candidate : Asmaa Zidan Poster #: B23
Calcitonin Gene-related Peptide Promotes the Healing of Corneal Epithelial Stromal Injury
Asmaa A . Zidan , Shuyan Zhu , Jia Yin
Purpose : Calcitonin gene-related peptide ( CGRP ) is an anti-inflammatory neuropeptide abundantly expressed by corneal nerves . Its effects on the corneal wound healing , inflammation , and opacity have not been studied before . In this study , we aim to examine the effects of CGRP on corneal epithelial stromal injury in mice .
Methods : Corneal epithelial stromal injury was induced in C57BL / 6 mice by removing the epithelium and anterior portion of the stroma using a hand-held Alger brush II . Following injury , mice were topically treated either with CGRP or PBS control three time daily for 14 days . Corneal epithelial healing , stromal opacity , and thickness were examined using slit lamp photography and OCT . Corneal endothelial cells integrity , alphasmooth muscle actin ( αSMA ) and TGFβ-1 expression were assessed by ZO-1 , αSMA , TGFβ-1 immunostaining , respectively . Leukocyte infiltration was determined using flow cytometry .
Results : CGRP accelerated epithelial wound healing and led to significantly reduced corneal opacity after injury . CGRP decreased CD45 + cell infiltration into the cornea from 10.2 ± 1.2 % to 6.1 ± 0.3 % ( P = 0.03 ) at day 5 . At day 14 , CGRP reduced corneal edema compared to PBS treatment ( central corneal thickness 159.7 ± 29.2 µ m in PBS group vs 85.2 ± 1 µ m in CGRP group , P = 0.03 ) and preserved corneal endothelial cell integrity .
Conclusions : CGRP promotes healing of corneal epithelial stromal injury by accelerating epithelial wound closure and preventing corneal opacification and edema . Potential mechanisms include inhibiting TGFβ-1 signaling and the production of αSMA , reducing leukocyte infiltration , and preserving corneal endothelial cells .