Oksijen endükte retinopiati in vivo fare modelinde intravitreal astaksantin enjeksiyonunun retinal endotelyal hücre proliferasyonuna, retina morfolojisine ve apoptotik hücre ölümüne etkisi

The aim of the study was to investigate the effects of astaxanthin, at different concentrations, on retinal endothelial cell proliferation, retinal morphological structure and apoptotic cell death in an in vivo oxygen-induced retinopathy (OIR) mouse model. A total of 30 C57BLJ/6 mice were used in this study. Twenty C57BL/J6 mice were exposed to %75 2 oxygen between postnatal 7-12 days. Mice were investigated in six groups. Group-A (n=5 eyes) contained negative control group, Group-B (n=5 eyes) contained control group without exposition to high oxygen and injection of 1µl intravitreal DMSO solution. Group-C (n=5 eyes) contained control group exposed to high oxygen without any injection. Group-D (n=5 eyes) contained control group exposed to high oxygen with injection of 1µl intravitreal DMSO solution (n= 5 göz), Group-E contained 10µg/ml intravitreal astaxanthin injected group and Group-F contained 100µg/ml intravitreal astaxanthin injected group. On postnatal day 12 1µl sterile DMSO solution was administered intravitreally to the right eye of 5 mice (Group-D), 10µg/ml to the right eye of 5 mice (Group-E) and 100µg/ml to the right eye of 5 mice (Group-F). Five mice of the same age that had been kept in room air without any exposition to high oxygen, were used as negative control group (Group-A). On day 17, mice were sacrificed and eyes enucleated for quantitative analysis of preretinal neovascularization, apoptotic cell death and morphological structure analyses. Neovascularization was quantified by counting the endothelial cell nuclei on the vitreal side of the inner limiting membrane of the retina. Histological and ultrastructural changes were examined by using light and electron microskopy. Apoptotic activity was analysed by using terminal deoxynucleotidyl transferase deoxy-UPT-nick end labeling (TUNEL) technique. The number of neovascular cell nuclei per histological section was not found statistically significant different between Group-A and –B (p=0,9). There was no statistically significant difference between Group-C and -D (p=0,3). There was significant difference between Group-A and Group-C and Group-B and –D (p<0.0001) (p<0,0001) . Compared with Group-D, the number of endothelial cell nuclei were decreased %77,49 in Group-E and %76,61 in Group-F. The number of neovascular cell nuclei per histological section was not found statistically significant different between Group-E and –F (p=0,9). In all groups histologic evaluation revealed, no cystic degeneration or cell loss. Compared with Group-C and -D, the number of atypical mitochondria detected by electron microscopy was lesser in astaxanthin injected groups (Group-E, -F). There was no significant difference between negative control group (Group-A) and Group-B. Statistically significant difference was seen when Group-A and Group-B compared with Group-C and –D (p<0.0001). There was also statistically significant difference when Group-C and –D compared with Group-E and –F (p<0.0001). No significant difference was detected between Group-E and-F. Analysis of apoptosis by TUNEL technique showed that in Group-A and Group-B apoptotic TUNEL-positive cells were at similar levels in the outer nuclear layer and inner nuclear layer. Similar levels in apoptotic TUNEL-positive cells were also detected between Group-C and –D. Comparing with group-C and -D, Group-A (p=0.3, 0.5) and –B (p=0.5, 0.7) showed no significant difference. There was no significant difference between Group-E and -F (p=0,3). Also no significant difference was seen when Group-E compared with Group-C and –D (p=0.09, p=0.2). Statistically significant difference was found when Group-F was compared with Group-C and –D (p=0.01, p=0.02). In conclusion astaxanthin supresses endothelial cell proliferationin in OIR mouse model. On morphological examination, astaxanthin did not show any toxic effect, on ultrastructural evaluation mitochondrial protective effect was observed and on TUNEL study antiapoptotoic activity was seen. Further studies are needed to determine the safety and efficacy of astaxanthin in neovascular ocular diseases.