Exploring Neuroprotective Effects of Gabapentin in Experimental Diabetic Retinopathy

Abstract

Introduction: Diabetic retinopathy (DR) is a main reason for vision loss worldwide. It is manifested by neurovascular dysfunction rather than pure vascular lesion.                                                                                                                   

 Aim of the work: This research aimed to examine the impact of gabapentin on diabetic retinal neurodegeneration induced by streptozotocin (STZ), identifying the crucial role of neurodegeneration in DR.                                                                                

Material and methods:  Forty-two adult male albino rats were randomly classified into three groups. Control group I: subdivided into subgroup Ia; plain control, subgroup Ib; vehicle control and subgroup Ic; positive control. Group II (Diabetic or STZ-treated group); administered STZ one time intraperitoneally at a dosage of fifty milligrams per kilogram, that was dissolved freshly in a 0.1 mole per liter citrate-buffered solution (pH 4.5). Animals detected with high levels of blood glucose of 250 milligrams per deciliter or greater forty-eight hours after STZ administration were classified as diabetic and included in the research. Group III (Gabapentin-treated diabetic group); The diabetic rats administered gabapentin orally by intragastric tube at a dosage of 300 milligrams per kilogram dissolved in distilled water twice daily for four weeks, following the administration of STZ at the same previous dosage. After four weeks, preparation of specimens of retinae was done for histological & immunohistochemical study using anti-caspase-3, anti-GFAP and anti-VEGF antibodies. Results were morphometrically & statistically studied.

Results: Diabetic group II revealed a significant decrease in the retinal sections thickness, reduced cell number of inner & outer nuclear layers and also a significant decrease in ganglion cells number. Significant upregulation of caspase-3, GFAP and VEGF immune reaction was observed. Gabapentin-treated diabetic group III showed preserved histological structure with retinal thickness restoration and down regulation of caspase-3, GFAP & VEGF immune reactions.

Conclusion: Gabapentin effectiveness in the prevention of neurodegeneration in rat models of diabetes was proved. Therefore, gabapentin might be considered as a valuable drug for future neuroprotective therapy.