Abstract
Purpose:
To investigate the effects of abundant breast milk nutrition on body weight gains, retinopathy, concentration of vascular endothelial growth factor (VEGF) in retina and insulin-like growth factor-1 (IGF-1) in serum and retina in oxygen-induced retinopathy (OIR) rat model.
Methods:
Neonatal Sprague-Dawley rats were divided into seven rat pups (7-rats group) or fourteen rat pups(14-rats group) after birth. Each group was put in cage with a dam. Some group were exposed to 80% oxygen (20.5 h) from postnatal day 0 (P0) to P12, and then placed in ambient air until P18. The groups in room air (RA) were used as a control. Body weight was measured every day. At P8, 13 or 18, rat pups were sacrificed and blood samples were collected. Retinas in left eyes were collected for ELISA, and retinas in right eyes were fixed, flatmounted and stained with adenosine diphosphatase. Retinal neovascularization in flatmounted retinas was scored (NV score), and total retinal areas (TRA) and avascular areas (AVA) were measured. From them a percent of avascular areas (%AVA) were calculated. Concentrations of VEGF and IGF-1 were measured with ELISA. Statistical analyses were performed with Mann-Whitney’s U test. P value <0.05 was considered significantly.
Results:
Body weight gains in 7-rats group were significantly greater than in 14-rats group from P3 through P18. Retinal VEGF levels in OIR were significantly lower at P8 and higher at P13 than in RA. In OIR, NV score and %AVA of smaller litters was higher than that of 7-rats group at P18. TRA of 7-rats group was significantly bigger than that of 14-rats group at P18 in both OIR and RA. In addition, TRA in OIR groups tended to be larger than in RA groups. IGF-1 levels in serum of 14-rats group were significantly higher than that of 14-rats group at P13 and 18 in both OIR and RA, however, retinal IGF-1 levels had no significant difference between 7-rats group and 14-rats group at any time points in neither OIR nor RA.
Conclusions:
In OIR model, the eye ball development appeared to be promoted by serum IGF-1 and oxygen exposure, whereas normal retinal vascular development was delayed by oxygen exposure. Consequently, AVA was relatively increased in 7-rats group OIR, more than in14-rats group. These results suggest that overnutrition intake may worsen the severity of OIR.
Keywords: 706 retinopathy of prematurity •
748 vascular endothelial growth factor •
618 nutritional factors