Age dependent effects of hypoxia-ischemia in neonatal mice brain

Goal was to determine differences in response to hypoxa-ischemia in the mouse brain at development stages representative of human preterm or term neonates, and to detect putative interference with spontaneous development from 2 to 15 days post-natal. Hypoxia-ischemia was realized in 5-day old and 10 day-old mice by unilateral permanent carotid ligature followed by 40 min oxygen restriction (8%). Ipsilateral hemisphere were collected at 3h, 6h 12h or 24h after hypoxia and pools of sex-equilibrated 4-6 brains were used for total RNA extraction at each time point. Co-hybridization of ishemic mRNA (labelled Cy5) and control tissues (labelled Cy3) were performed on Agilent (design 026655) micro-arrays in three independent experiments. In order to evaluate hypoxia ischemia interference during development, we evaluated spontaneous expression at P5 and P10 (Cy3) and extented the observations in a separate set of tissues extracted at P2 and P15. Two color experiments : ischemic hemisphere (Cy5)/control tissue from untreated animals (Cy3). Moreover, P2 and P15 extracts each hybridized in two colors dye-swap.