INTRODUCTION: Carvacrol (CV) is a phenolic monoterpenoid found in essential oils of aromatic plants. In the present study, we investigated the potential protective effect of CV against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats.
METHODS: 18 male adult Wistar albino rats (250-400g) were randomized into 3 equal groups comprising 6 animals in each. Group-1 (control group) received intraperitoneal (i.p.) saline solution (0.5 ml/200 g) weekly for 4 weeks. Group-2 received i.p. PTX (5mg/kg) while Group-3 received i.p. CV (25mg/kg) 30 minutes after i.p. PTX (5mg/kg) weekly for 4 weeks. At the end of the experimental period retinal and optic nerve tissues were evaluated histopathologically.
RESULTS: All retinal specimens in Group-1 (control) were histopathologically normal. In Group-2 (PTX) all eyes (6/6) demonstrated increased retinal vascularity and rosette-like structures in the outer nuclear layer while in Group-3 (PTX-CV), all eyes (6/6) demonstrated normal retinal vascularity and absence of rosette-like structures. All optic nerve specimens in Group-1 (control) were histopathologically normal. In Group-2 (PTX), all eyes (6/6) demonstrated severe vacuolization and reduction in the number of astrocytes and oligodendrocytes in optic nerve specimens while 3 eyes (3/6) demonstrated marked single cell necrosis. None of the eyes in Group-3 (PTX-CV) demonstrated either vacuolization or reduction in the numbers of astrocytes and oligodendrocytes. No remarkable single cell necrosis was observed in optic nerve specimens of Group-3 (PTX-CV).
DISCUSSION AND CONCLUSION: Our histopathological findings demonstrated the protective role of CV against PTX-induced cytotoxicity. CV might be a promosing molecule in counteracting oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.