PPAR-α Agonist Fenofibrate Suppressed the Formation of Ocular Surface Squamous Metaplasia Induced by Topical Benzalkonium Chloride

PURPOSE. To investigate the effects and mechanisms of the peroxisome proliferator-activated receptor alpha (PPAR-alpha) agonist fenofibrate on the formation of ocular surface squamous metaplasia induced by topical benzalkonium chloride (BAC) in a mouse model. METHODS. Ocular surface squamous metaplasia was induced in 16 days by topical BAC application in mice. During the period of induction, mice were divided into four groups: no additional treatment (BAC+UT), topical vehicle (BAC+Vehicle), topical fenofibrate (BAC+Feno), or topical fenofibrate plus intraperitoneal injection of MK886 (BAC+Feno+ MK886). The parameters of tear film were evaluated on day 16, and eye specimens were collected. Histologic investigation; PAS assays; immunostaining for cytokeratin 10 (K10), Ki67, and F4/80; and PCR assays for TNF-alpha and IL-6 were performed. Cell Counting Kit 8 (CCK-8) assays were performed to evaluate the inhibitory effects of fenofibrate on RAW264.7 cells. RESULTS. Fenofibrate suppressed the formation of BAC-induced instable tear film. In the BAC+Feno group, the expression of K10 and Ki67 was lower than in the other three groups. The number of goblet cells was reduced in eyes of the BAC+UT and BAC+Vehicle groups but was maintained in eyes of the BAC+Feno group. The number of F4/80positive cells and the levels of TNF-alpha and IL-6 mRNA were significantly reduced in the cornea of the BAC+Feno group. These effects of fenofibrate could be attenuated by MK886. The cell viability of RAW264.7 cells could be significantly inhibited by fenofibrate in a dose-dependent pattern. CONCLUSIONS. Topical application of fenofibrate suppressed the formation of ocular surface squamous metaplasia, which might be mediated through the PPAR-alpha signaling pathway.