A Novel Topical Ophthalmic Formulation to Mitigate Acute Mustard Gas Keratopathy In Vivo: A Pilot Study

This pilot study investigated the in vivo therapeutic potential and tolerability of a multimodal ophthalmic formulation, topical eye drops (TED), for acute mustard gas keratopathy (MGK) using a rabbit model. Twenty New Zealand White rabbits were used. Only right eyes of 18 rabbits (oculus dexter [OD]) received single sulfur mustard gas (SM) vapor injury, whereas contralateral eyes were left untreated or received TED for tolerabilty evaluation. Two rabbit eyes received no treatment and served as age-matched naive control. The four groups were: Naive (oculus sinister [OS] untreated eyes; n = 9); TED (OS treated only with TED BID for 3 days; n = 9); SM (OD exposed to SM vapor; n = 9); and SM+TED (OD exposed to SM+TED BID for 3 days; n = 9). Ocular examination in live rabbits were performed utilizing slit-lamp biomicroscopy, Fantes grading system, fluorescein staining, Schirmer's tests, pachymetry, and applanation tonometry. Cellular and molecular changes in rabbit corneas were assessed after humane euthanasia on day-3 and day-7 with histopathological and real-time polymerase chain reaction PCR techniques. TED to rabbit eyes was found tolerable in vivo. SM-exposed eyes showed significant increase in Fantes scores, central corneal thickness (CCT), Schirmer's test, epithelium-stroma separation, and corneal edema. TED mitigated clinical symptoms by reducing corneal edema, Fantes scores, CCT, and Schirmer's test. Further, TED decreased SM-induced corneal haze, inflammatory and profibrotic markers, transforming growth factor-TGF-β1 and cyclooxygenase-2COX-2, and damage to corneal structure, including epithelial-stromal integrity. The developed multimodal eyedrop formulation, TED, has potential to mitigate acute MGK effectively in vivo. TED is effective against MGK.