Kiwifruit extract attenuates tadalafil induced retinal injury in adult male albino rats: a histological and immunohistochemical study

Abstract

Background: Tadalafil is a one of the commonly prescribed drugs for treatment of erectile dysfunction. Several ocular side effects have been reported with tadalafil therapy. Kiwi fruit is a popular fruit that has a wide range of pharmacological activities and a proposed role in combating serious ocular complications.Aim: To evaluate the potential protective role of kiwi fruit extract (KFE) against tadalafil induced retinal injury in adult male albino rats.Material and Methods: Thirty adult male albino rats were divided into four groups; control group, KFE-treated group (500 mg/kg), Tadalafil-treated group (1.8 mg/kg), and both Tadalafil & KFE-treated group. Animals were orally administered once daily for six weeks. Specimens from the retina were processed for light and electron microscopy. Immunohistochemical study was performed using antibodies against B-cell lymphoma 2 (Bcl-2).Results: Specimens from tadalafil-treated animals showed a statistically significant decrease in the total retinal thickness and the ganglion cell number. The retinal pigmented epithelium was detached. The inner segment of the photoreceptor was irregularly oriented with interrupted outer limiting membrane. Dark pyknotic nuclei were observed in the outer and inner nuclear layers and the ganglion cell layer. Ultrastructurally, disorganized membranous discs with increased inter-disc spaces of the outer segment, cytoplasmic vacuoles and swollen mitochondria of the inner segment of the photoreceptor layer and shrunken irregular cell bodies and nuclei of the outer and inner nuclear and ganglion cell layers were observed. The immunohistochemical study showed a significant decrease in Bcl-2 immunoreaction. In contrast, minimal changes were observed in rats treated concomitantly with both tadalafil and kiwi fruit extract, with a non-significant decrease in the immunoreaction.Conclusion: Tadalafil induced structural changes in the retina of adult albino rat that could be ameliorated by concomitant treatment with kiwi fruit extract.