engleski

Lifelong changes in perineuronal nets and the learning behavior in rats after mild perinatal hypoxic brain lesion

This study investigates changes in neuronal connectivity and cognitive abilities after mild perinatal hypoxic brain lesion in a new non- invasive model of brain injury in rats. For the purpose of this research, nineteen Wistar Han® (RccHan®:WIST) rats, (9 females and 10 males) were randomly divided into hypoxic and control group on postnatal day 1 (P1) when hypoxia was induced in a warm (≈ 25°C) hypobaric chamber (Atm350mmHg, pO273mmHg) during 2 hours, while controls were kept in normal housing conditions. Behavioral tests were performed at P30 and P70 using the open field, hole board, social choice, and T-maze tests. Samples of brain tissue from adult animals (P105) were used for histochemical examination of cytoarchitectonics (Nissl staining), interneurons (parvalbumin immunohistochemistry) and perineuronal nets (Wisteria floribunda agglutinin, histochemistry). After this non- invasive hypoxic brain injury, histo- architectonics and the laminar and structural organization of the rat telencephalon, as well as motor and socialization patterns were preserved. However, distinct changes in morphology, number, and distribution of the parvalbumin-immunoreactive neurons and perineuronal nets in the midcingulate cortex, hippocampus, and somatosensory cortex were observed. Injured animals also show significantly impaired learning behavior. Thus, the mild perinatal hypoxic brain lesion in the rat leads to disturbances in brain connectivity responsible for learning and cognitive processes that are not compensated after the provoked hypoxia. Further characterization and evaluation of this brain injury model, on molecular, cytological and connectivity levels, is needed. Acknowledgments Research was funded by the Scientific Centre of Excellence for Basic, Clinical and Translational Neuroscience (project “Experimental and clinical research of hypoxic ischemic damage in perinatal and adult brain” GA KK 01 1 1 01 0007 funded by the European Union through the European Regional Development Fund) and Croatian Science Foundation.

neuronal connectivity ; learning ; hypoxia ; brain development

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