Bromhexine elevates REP2 expression to stimulate secretion from human primary conjunctiva fornix epithelial cells.

Bromhexine was reported to relieve the symptoms of Sjogren Syndrome at an early stage. However, the underlying mechanism remains unclear. Here, we administered bromhexine at low doses in human primary conjunctival fornix epithelial cells, and found it stimulated MUC5AC secretion and lipid droplet production. Expression of the metabolism-related gene CHML was also upregulated by bromhexine treatment, and REP2, the protein produced by the CHML gene, was induced. These results suggest that bromhexine is a potential candidate eye drop drug for the treatment of multiple types of dry eye disease, not only limited to the treatment of dry eyes in Sjogren Syndrome.