Characteristics of Glial Reaction in the Perinatal Rat Cortex: Effect of Lesion Size in the ‘Critical Period’

[摘要] In this study we investigate the capability oflesions, performed between embryonic day E18and postnatal day P6, to provoke glial reaction.Two different lesion types were applied: ‘severe’lesion (tissue defect) and ’light’ lesion (stabwound). The glial reaction was detected withimmunostain[ng against glial fibrillary acidicprotein. When performed as early as P0, severelesions could result in reactive gliosis, whichpersisted even after a month. The glial reactionwas detected at P6/P7 and became strong by P8,regardless of the age when the animals werelesioned between P0 and P5. Namely, a strictlimit could be estimated for the age whenreactive glia were already found rather than forthe age when glial reaction-provoking lesionscould occur. After prenatal lesions, no glialreaction developed, but the usual glia limitanscovered the deformed brain, surface. Lightlesions provoked glial reactions whenperformed at P6. In conclusion, three scenarioswere found, depending on the age of the animalat injury: (i) healing without glial reaction,regardless of the remaining deformation; (ii) depending on the size of the lesion, either healing without residuum or with remainingtissue defectplusreactive gliosis; and (iii) healing always with reactive gliosis. The age limits between them were at P0 and P5. The glial reactivity seemingly appears after the end of the neuronal migration and just precedes the massive transformation of the radial glia into astrocytes. Estimating the position of the appearance of glial reactivity among the events of cortical maturation can help to adapt the experimental results to humans.

[学科分类] 精神健康和精神病学