Abstract
Abstract: :
Purpose: We previously reported that the conjunctival epithelium secretes GSH. In this study, we determined the effect of Ad5 infection on GSH turnover and transport in pigmented rabbit conjunctiva. Methods: In anesthetized rabbits 106 PFU of Ad5 was topically applied over newly scarified corneal epithelium. Conjunctival tissues (control or day 3 post-inoculation) were excised and mounted as flat sheets in a modified Ussing chamber at 37°C. Bioelectric parameters were monitored every 15 min with an automatic voltage clamp device. Unidirectional fluxes of 3H-GSH (and 14C-D-mannitol as a paracellular marker) were determined under conditions of inhibited GSH biosynthesis (10 mM BSO) and degradation (1 mM acivicin). Total intracellular GSH levels were determined in control and Ad5 infected conjunctival tissue. Results: The short circuit current and potential difference across conjunctival tissues of Ad5-infected rabbits were decreased by ≥50% compared to control. Ad5 inoculation significantly (p<0.05) decreased conjunctival GSH levels by 19%, 45%, 48%, and 50% at 8, 24, 48, and 72 hrs, respectively. In control rabbits, the apparent permeability (Papp) of GSH was 4.7 0.2 vs. 7.3 0.3 10-5 cm/s in the mucosal-to-serosal (M to S) vs. serosal-to-mucosal (S to M) directions, respectively. In Ad5 rabbits the Papp in M to S direction (2.5 0.3 10-5 cm/s) was not significantly different from that in the S to M direction (2.2 0.3 10-5 cm/s). The Papp of D-mannitol was the same in either direction and did not change between control and Ad5-infected rabbits. Conclusion: Net secretion of GSH across rabbit conjunctiva was significantly diminished with Ad5 infection. Active ion transport rate was also ∼50% lower. A decrease in GSH secretion into mucosal fluid with Ad5 infection may have been caused by decreased intracellular pool size.
Keywords: 307 adenovirus • 321 antioxidants • 365 conjunctiva