Levels of mucin gene expression in normal human conjunctival epithelium in vivo

PURPOSE: Conjunctival impression cytology (CIC) samples were used to determine the mean and normal range of mRNA levels of human MUC1, MUC2, MUC4, MUC5AC, and MUC7 mucin genes. METHODS: Real time PCR was performed to determine normal mRNA levels in CIC samples of 24 male and 19 female healthy donors. Correlation coefficients between gene expression levels were obtained. RESULTS: All five mucin genes were expressed in the CIC samples. MUC1 and MUC4 were present at the highest level and MUC2 was at the lowest. There were no gender differences. Significant positive correlations existed between MUC2 and MUC4 and between MUC2 and MUC7 levels. CONCLUSIONS: Normal levels and ranges of mRNAs for MUC1, MUC2, MUC4, MUC5AC and MUC7 conjunctival mucin genes have been established for the first time. These data may serve as the normal threshold values for future comparisons in different experimental and pathological conditions involving the ocular surface.