Tear film mucin (MUC)

Tear film mucins are high-molecular-weight glycoproteins that are fundamental to the stability and protective function of the ocular surface (Gipson, 2004, PMID: 14967200). They are categorized into membrane-associated mucins (e.g., MUC1, MUC4, MUC16), which form the glycocalyx on the corneal and conjunctival epithelium, and gel-forming secreted mucins (primarily MUC5AC), which are produced by conjunctival goblet cells (Mantelli & Argüeso, 2008, PMID: 18554540). These mucins transform the hydrophobic ocular surface into a hydrophilic one, allowing the aqueous tear layer to spread evenly and providing a barrier against pathogens and mechanical friction. In conditions like dry eye disease, mucin production is often diminished or altered, leading to tear film instability and epithelial damage (Pflugfelder & Paiva, 2017, PMID: 28603015). Therapeutic strategies involve the use of mucin secretagogues such as diquafosol and rebamipide to restore the mucin layer, as well as anti-inflammatory agents to prevent the loss of goblet cells (Koh, 2016, PMID: 27553915).

Other names

Ocular mucinsConjunctival mucinsCorneal mucinsMucin glycoproteinsTear film mucin and ocular surface

Mucin secretagogues like diquafosol act as P2Y2 receptor agonists to stimulate mucin release from goblet cells, while rebamipide increases the expression of membrane-associated mucins; anti-inflammatory agents help maintain the health of mucin-producing cells.