Connective Tissue Growth Factor Localization in Vascular and Avascular Retinas of some Vertebrate Species

The connective tissue growth factor (CTGF/CCN2) is engaged in structural retinal vascular changes and in the retina's vascular beds.CTGF immunohistochemical expression was done in the vascular and avascular retinas of mammals, birds, and reptilians.The results indicated CTGF immunostaining was detected in the intraretinal blood vessels of the studied mammalian vascular retina (Balb/C, Acomys russatus, Mesocricetus auratus), while CTGF expression was absent in intraretinal blood vessels and was detected in choriocapillaris of the avascular mammalian retina (Rousettus egyptiacus, Jaculus jaculus, Paraechinus aethiopicus).The avascular retinas of studied avian species (Falco tinnunculus, Columba livia, Merops superciliosus, Ammoperdix heyi) exhibited negative immunostaining of CTGF in retinal layers.The avascular retinas of studied reptilian species (Ptyodactylus hasselquistii and Chalcides ocellatus, Uromastyx aegyptius) showed a strong CTGF expression level in some layers of retina but other reptilian species retinas (Acanthodactylus boskianus, Trachemys scripta elegans, Scincus mitranus) showed negative CTGF localization.The study concluded that CTGF/CCN2 signalling is involved in the intraretinal blood vessels of the vascular retina and was not included in avascular retinas except in some species of reptiles, which need more study.