Objective To evaluate the expression levels of inter cellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), Integrin-α4β1 and fibronectin after hypoxic-ischemic brain injury induced by partial occlusion of the umbilical cord (PCO) in fetal lambs.
Methods Nine fetal lambs at 86–92% gestation were randomly assigned to three experimental groups: one healthy group (sacrificed 3 h after delivery) and two hypoxic-ischemic groups: one sacrificed immediately after HI event (HI-0h) and the other sacrificed 3 h after HI event (HI-3h). Injury was induced by PCO during 60 min. Brains were perfusion-fixed and divided into different cerebral regions which were disaggregated and immunolabelled for ICAM-1, VCAM-1, Integrin-α4β1 and fibronectin. Cell suspensions were analyzed by flow cytometry. ANOVA (p<0.05).
Results HI-0h group showed a decrease in the percentage of positive cells (p<0.05), in comparison to healthy ones, in all regions studied for Integrin-α4β1 and fibronectin (except in the hippocampus). With respect to VCAM-1 and ICAM-1, a statistically significant decrease was only found in the cortex. Three hours after injury, Integrin-α4β1 maintained low levels in comparison to the healthy group in all brain regions, whereas this was only true of fibronectin in the cortex, cerebellum and thalamus. VCAM-1 and ICAM-1 differ in the cortex and cerebellum. In the comparison of both HI groups, both Integrin-α4β1 and fibronectin showed an increase in cortex and medulla oblongata, after 3 h, whereas VCAM-1 decreased (p<0.05) in all brain regions (except hippocampus).
Conclusion Our data suggest a decrease in the expression of adhesion molecules just after HI brain injury.
Grants: “Fundación Jesús-Gangoiti-Barrera”, UPV/EHU06/99, Basque-Government (IT-287-07) and FIS06/0908.