Rescue of conjunctival lymphatics after mitomycin C induced inhibition in rat eyes: An experimental study

This experiment was designed to study the effect of mitomycin C (MMC) on conjunctival lymphatics and the lymphangiogenesis potential of synthetic retinoic acid (ec23) in rat eyes. This prospective animal experimental study included 30 Sprague-Dawley rats, and they were allocated into five groups. The right eye underwent localized subconjunctival surgical trauma with a 31-G needle, along with subconjunctival injection of either balanced salt solution, 0.01% MMC, 100 nM ec23, 0.01% MMC with 100 nM ec23, or 0.1% dimethyl sulfoxide in the right eye. The left eyes were control. Enucleation was done on post-operative day 14, and each conjunctival specimen was stained with Masson trichome, CD 31, and D2-40 to study fibrosis, vascular and lymphatic density, respectively. The main outcome measured was the density of conjunctival lymphatic vessels at the surgical site. It was noted that MMC resulted in a significant reduction in conjunctival lymphatic and vascular density in comparison with the control eyes (179 ± 21.33 vs 85 ± 30.82 and 190 ± 18.71 vs 85 ± 30.82 P = .009), whereas 100 nM ec23 caused significant increase in lymphatic vessel density in comparison with control eyes (310 ± 82.16 Vs 134 ± 32.09, P = .008). Similarly, 100 nM ec23 significantly increased conjunctival lymphatic density in 0.01% MMC-treated eyes (1000 ± 374.17 vs 388 ± 121.53, P = .016). Inter-group analysis showed that combined use of 100 nM ec23 caused the highest lymphatic (1000 ± 374.17, P = .001) and blood vessels (596 ± 294.67, P = .014) density. Masson trichome score (fibrosis) between intervention and control eyes was compared across different groups, and it was statistically insignificant. To conclude, MMC caused a significant reduction in lymphatic vessel density, and application of 100 nM ec23 resulted in significant lymphangiogenesis in both MMC-exposed and non-MMC-exposed eyes.