Comparative study about ageing effect on retina and cerebellum of Columba livia domestica

Abstract

The present research explores the ageing impact of Columba livia domestica on retina and cerebellum. It is an available and a widespread bird species. Three ageing groups (n = 5) of male Columba were collected at about three weeks, six months and five years old. Histological studies were made. Morphometric measurement of both retinal and cerebellar cortex layer thicknesses has been determined. For evaluation of the neuronal synapses, quantitative GFAP biochemically and immunohistochemically staining was performed. Also, biochemical analysis of glucose transporter 1, serotonin and dopamine was carried out to demonstrate their functional activity.Flow cytometric assessments of quantitative cell death were accomplished by using annexin V. The present findings revealed quantitative and qualitative increase of GFAP parallel with decrease of serotonin, dopamine and glucose transporter 1 as well as increase of UR and LR annexin V reflecting cell death in old groups. These were confirmed by damaging of the retina and cerebellar layers. The present findings concluded that retinal and cerebellar cells associated with ageing were determined by sharp rise in both cell death and GFAP levels. Additionally, a decrease of dopamine, serotonin and GluT1 level manifested maybe led to functional alteration of both retina and brain. K E Y W O R D Sageing, annexin V, cerebellum, Columba livia domestica, histology, retina | 395 SABRY triggered during flight by acquiring information about the optic flow (Wylie et al., 2018). In pigeons, the visual motion takes place throughout the retina via self-motion as self-rotation and self-translation is affected by information inputs in vestibulocerebellum (Wylie, 2013). Both retina and cerebellum also play an essential role for locomotion of pigeons for food collection and avoiding predators (Dhawan, 1991). Consequently, both retina and cerebellum are of great importance in managing the pigeon activity.Birds showed higher metabolic rate (2-2.5 times) (Butler, 2016) and two-to-three times longer life spans compared to mammals of the same size (Travin & Feniouk, 2016). These may result from certain adaptation for inhibiting ageing-related damage induced by reactive oxygen species and formation of glycation end products (Holmes, Fluckiger, & Austad, 2001). Also, birds characterized by their higher body temperature (3-5°C) and blood glucose (2-4 times) than mammals (Ritchie, Harrison, & Harrison, 1994) of similar body mass. Mammalian and avian species of more than one kilogram showed blood glucose concentration within the range of about 135 and 275 mg/dl, respectively (Braun & Sweazea, 2008). These manifestations supposed to accelerate ageing in birds due to the production of glycosylated proteins via Maillard reaction (Monnier, 1990;Kristal & Yu, 1992). However, they show increased longevity (Skujina, McMahon, Lenis, Gkoutos, & Hegarty, 2016). This arouses curiosity about the comparable changes of ageing among avian and mammalian species (Holmes et al., 2001) and attracts many authors such as Holme...