Connexin expression patterns in diseased human corneas

The present study aimed to explore the feasibility of using antisense connexin (Cx) treatment to promote corneal wound healing, and to investigate the changes of Cx gap junction proteins in terms of mRNA, protein expression and distribution in human corneas that were diseased due to various causes. A total of 13 diseased corneas were studied, which were obtained from five eyes injured by chemical burns, five infected eyes and three eyes with Stevens-Johnson syndrome (SJS)-affected corneas. Total RNA was extracted from the corneas and processed by qPCR with isoform primers to detect the expression of eight Cxs. Flow cytometry was adopted to determine the differences in the expression levels of Cx26, Cx31.1 and Cx43. Immunofluorescence was employed to show the localization of the three aforementioned Cxs. The qPCR results indicated that of the eight Cxs, only Cx26, Cx31.1 and Cx43 were upregulated in diseased corneas. Flow cytometry showed that all the diseased corneal tissues, with the exception of the SJS-affected corneas, showed a significantly higher percentage of cells that expressed Cx26 and Cx31.1 compared with the percentage in normal corneas (P<0.05). For Cx43, all three injured corneal groups showed a significantly higher percentage of cells that expressed Cx43 compared with the percentage in normal corneas (P<0.05). Immunohistochemical staining showed that the localization of Cx26, Cx31.1 and Cx43 differed between normal corneas and diseased corneas. This study elucidated the alteration of Cx expression patterns in several corneal diseases. The results indicated that Cx26, Cx31.1 and Cx43 are upregulated in chemically burned and infected corneas at the mRNA and protein levels, whereas only Cx43 is upregulated in SJS-affected corneas.