Purpose:
To investigate the effects of abundant breast milk intake on body weight gain, retinopathy, concentration of vascular endothelial growth factor (VEGF) in retina and concentration of insulin-like growth factor-1 (IGF-1) in serum in a rat model of oxygen-induced retinopathy (OIR).
Methods:
Neonatal Sprague-Dawley rats were divided two groups; one was a group consisted of seven rat pups (7-rats group) to let them have more amount of milk intake. And the other was consisted of fourteen rat pups (14-rats group) as a control. Each group was put in a cage with a mother rat. The rats were exposed to daily cycles of 80% oxygen (20.5 h), ambient air (0.5 h), and progressive return to 80% oxygen (3 h) from postnatal day 0 (P0) to P12, and then the rats were placed in ambient air until P18. The mother rats were rotated every two days. Body weight of rat pups were measured everyday. At P13 and P18, rat pups were sacrificed, and then blood was collected from the left ventricle. Retinas in left eyes were collected for ELISA, and retinas in right eyes were fixed, flatmounted and stained with ADPase. Concentrations of VEGF in retina and of IGF-1 in serum were measured by ELISA. In the stained retinal flatmounts, retinal neovascularization was scored (NV score), and avascular areas were measured as a percent of total retinal area (%AVA) using Image J software (NIH). Statistical analyses were performed with Mann-Whitney’s U test. P value <0.05 was considered significantly.
Results:
The body weight of rats in 7-rats group increased significantly greater than in 14-rats group from P3. The results were shown at Table 1. At P13, there was significant difference in concentration of IGF-1 in serum and %AVA. NV did not occur at P13. At P18, there was significant difference in concentration of VEGF in retina and IGF-1 in serum.
Conclusions:
The more amount of milk intake increased body weight gain, concentration of VEGF in retina and of IGF-1 in serum significantly but not affected on retinopathy in the rat model of OIR.
Keywords: retinopathy of prematurity • nutritional factors • vascular endothelial growth factor