Histological Changes Induced By Sildenafil Citrate on Adult and Senile Optic Nerve of Albino Rats

Abstract

SUMMARY S ildenafil citrate is one of the most commonly used drugs worldwide and the drug has proved its great effect in treatment of erectile dysfunction in men of different ages, but it has been found that the drug has multiple adverse effects which appear when the drug used in high doses and for long duration. These adverse effects include headache hypotension, facial flushing, indigestion and nasal congestion. It has been found that one of the most important adverse effects of sildenafil is non artertic anterior ischemic optic neuropathy (NAION) which appears in the form of sudden painless loss of vision which has been spread greatly between users of the drug. WHO reports a large number of NAION cases of different ages every year but most of these cases are old age who suffer from diabetes mellitus, atherosclerosis, hypotension or hypercholestramia which considered to be important risk factors for development of the disease. Multiple studies have discussed the causal relation between usage of sildenafil citrate and development of NAION but all these studies concentrated on the clinical aspects of the disease, so the main aim of this study was focusing on the histological changes induced by application of sildenafil citrate on adult and senile optic nerve of albino rats. Twenty four rats had been used in this study and they were divided into 4 groups: - Group1 (adult control group): this group consisted of 6 adult rats, they received oral DMSO,.2% for 30 days. - Group2 (senile control group): this group consisted of 6 senile rats, they received oral DMSO,.2% For 30 days. - Group3 (adult experimental group): this group consisted of 6 adult rats, they received oral sildenafil citrate 1.43mg/kg dissolved in DMSO,.2% for 30 days. - Group4 (senile experimental group): this group consisted of 6 senile rats, they received oral sildenafil citrate 1.43mg/kg dissolved in DMSO,.2% for 30 days. The rats were sacrificed after 4 weeks and the optic nerve was dissected and fixed in 10% formaldehyde for H&E and luxol fast blue stain and glutraldhyde 2% for semithin sections, Epon blocks and toludine blue stain. When samples are examined it revealed that: By examination of H&E sections, the adult control group revealed that the optic nerve consisted of nerve fibers and each one of them surrounded by oligodendrocytes, nuclei of astrocytes in between, the nerve surrounded by three meningeal layers arranged from outside to inside dura matter, pia matter