The possible ameliorative effect of granulocyte colony stimulating factor on rotenone -induced changes in the retinal photoreceptors of rats: Histological and immunohistochemical study

Introduction: Rotenone is an odorless isoflavone used as an insecticide, and piscicide. It is a potent inhibitor of the mitochondrial respiratory chain complex I leading to oxidative stress that ends with cell death. Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein cytokine and a hematopoietic growth factor, produced by many cells. It promotes cell proliferation, survival, and mobilization. It also has anti-inflammatory and anti-apoptotic actions. Aim: This study aimed to investigate the ameliorative effect of G-CSF in a rat model of rotenone-induced retinal photoreceptors' changes. Materials and Methods: 25 male Wistar rats were used and were divided in to 3 groups; Control group; ROT group: By which rats received 30 mg/kg/day rotenone suspended in 0.25 ml 0.5% CMC orally beginning from 1st day of the experiment till 28th day; and G-CSF group: which was the rotenone group rats that further treated with 50 μg/kg/day G-CSF in 0.1 ml 5% dextrose subcutaneous for 15 days beginning from the 29th day till the 43rd day of the experiment. Results: H & E results of the ROT group showed outer & inner segments with extensive structural damage, nuclear fragmentation, besides karyorrhexis, and karyolysis, together with vacuolations of the synaptic region. Also, significant increase of caspase-3 while, decrease of N-cadherin immunohistochemical expression. The EM findings revealed extensive degenerative changes in the all segments of the photoreceptors besides significantly increased malondialdehyde levels. Conclusion: G-CSF can ameliorates rotenone-induced degenerative structural changes in rat's retinal photoreceptors. This was through its anti-apoptotic and anti-inflammatory actions. So, G-CSF is a promising neuroprotective drug for retinal diseases and/or injuries.