Glial activation in white matter following ischemia in the neonatal P7 rat brain.pdf

1 Cet article a été accepté dans la revue Experimental. Neurology. Regular article - Development Glial activation in white matter following ischemia in the neonatal P7 rat brain Valérie Biran1,2, Luc-Marie Joly1, Anne Héron3, Agnès Vernet1, Céline Véga1, Jean Mariani1, Sylvain Renolleau1,4 and C. Charriaut-Marlangue1,# 1UMR-CNRS 7102, Université Pierre et Marie Curie, 9 quai St-Bernard, 75005 Paris 2Service de Néonatologie, H?pital Armand Trousseau, 75012 Paris 3Université René Descartes, 75006 Paris, France 4Service de Réanimation, H?pital Armand Trousseau, 75012 Paris. Text : 5960 words Tables : 2 Figures : 7 #Correspondence : C. Charriaut-Marlangue UMR-CNRS 7102, HICD, case 14 9 quai St-Bernard 75005 Paris, France. Tel : 33 1 44 27 32 32 Fax : 33 1 44 27 22 80 Email : Christiane.Marlangue@snv.jussieu.fr 2 Support: The Foundation Cino del Duca supported this work. ABSTRACT This study examines cell death and proliferation in the white matter after neonatal stroke. In post-natal day 7 injured rat, there was a marked reduction in myelin basic protein (MBP) immunostaining mainly corresponding to numerous pyknotic immature oligodendrocytes and TUNEL-positive astrocytes in the ipsilateral external capsule. In contrast, a substantial restoration of MBP, as indicated by the MBP ratio of left-to- right, occurred in the cingulum at 48 (1.27 ± 0.12) and 72 (1.30 ± 0.18, p0.05) hours of recovery as compared to age-matched controls (1.03 ± 0.14). Ki-67 immunostaining revealed a first peak of newly-generated cells in the dorsolateral hippocampal subventricular zone and cingulum at 72 hours after reperfusion. Double immunofluorescence revealed that most of the Ki-67-positive cells were astrocytes at 48 hours and NG2 pre-oligodendrocytes at 72 hours of recovery. Microglia infiltration occurs over several days in the cingulum and a huge quantity of macrophages reached the subcortical white matter where they engu