Abstract

Objectives: Ethambutol (EMB) induced ocular toxicity The current study was designed to check the ethambutol (EMB) induced histological changes in optic nerve of rabbit.  Study Design: An experimental Randomized Control Trial (RCT). Place and Duration: The study was conducted in the experimental research Laboratory of University of Health Sciences, Lahore from January 2009 to December 2009. Material & Method: Ten, New Zealand white, albino rabbits of either sex, 6-12 month old, weighing 1- 2 kg were randomly divided in to two groups comprising five animals in each. Group A served as control, while Group B was given ethambutol 100 mg/kg/day for four weeks. At the end of experimental period, each animal was sacrificed under chloroform and both optic nerves along with chiasma were taken out and preserved. In this way, twenty optic nerve specimens (ten for each group) were collected from ten albino rabbits
Results: The histological study showed that optic nerves of group A were quite normal, while the histological preparation of group B showed decrease diameter of optic nerves and cytoplasmic vacuolations. Statistical analysis was done using Independent “t” test for measurement of diameter of optic nerve and counting the number of vacuoles. The results showed an immense vacuolations (p < 0.05) and decrease in diameter of optic nerve (p > 0.05) in the sections from group B as compared with that in the group A. However, there was no evidence of inflammatory changes and myelin-like structure in any preparation from the two groups Conclusion: Ethambutol(EMB) induced histological changes produce vacuoles, representing damage to the optic nerve.