Effects of long-term passive smoking on vascular endothelial growth factor and apoptosis markers expression in lens and corneal epithelial cells: An experimental study*

Authors: FATİH ÖZCURA, SEMA ORUÇ DÜNDAR, İBRAHİM METEOĞLU, MEHMET ERKUT KARA

Abstract: Aim: To determine the effects of smoking on vascular endothelial growth factor (VEGF) expression and apoptosis in lens and corneal epithelial cells. Materials and methods: This experimental study included 38 Sprague-Dawley rats. Rats were randomly assigned into 4 groups. Groups 1 (males) and 2 (females) were exposed to smoke beginning on the 21st day after birth, whereas groups 3 (males) and 4 (females) were not exposed to smoke. At the end of the fourth month, right eyes of all rats were enucleated. Immunohistochemical analysis was performed in enucleated eyes in terms of VEGF and apoptosis markers, namely caspase-3, Bcl-X, and p53. Comparisons between the groups were performed using the Mann-Whitney U test. Results: There was no significant difference in the lens epithelial cells in terms of VEGF and apoptosis markers between the rats exposed to smoking and those not exposed. However, there was a significant increase in VEGF expression among female rats exposed to smoking while there was no significant difference in terms of apoptosis markers between the groups in corneal epithelial cells. Conclusion: Our findings show that smoking does not affect the VEGF and apoptosis markers in lens epithelial cells, but it significantly increases the VEGF expression in corneal epithelial cells among female rats. In our opinion, the increase in the dry eye symptoms due to smoking may be caused by the differences in tear composition from change in permeability of the ocular surface vessels related to VEGF.

Keywords: Smoking, vascular endothelial growth factor, apoptosis, lens, cornea

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