Modifications in perineuronal nets within the rat vestibular nuclei during postnatal development and in injury

Abstract

To determine whether perineuronal nets (PN) within the vestibular nuclei contribute to plasticity of central connectivity, we studied the presentation of PN within the vestibular nuclei during development (rats, P1 to adult) and after unilateral labyrinthectomy (UL) in the adult. Histochemistry with the lectin Wisteria floribunda agglutinin was used to map PN about NeuN-immunopositive neurons within the vestibular nuclei. In normal postnatal rats, PN was detectable by P3 in the vestibular nucleus as fuzziness about neuronal cell bodies. From P9 onwards, the fuzzy PN progressively consolidated into a network organization. The fuzziness was no longer observable after P12. During postnatal development, the number of neurons showing PN increased with age, reaching the adult level by P21. With UL, the PN network on the lesioned side remained compact until 5 days post-lesion when the fuzziness reminiscent of that in early postnatal rats became evident. By 11 days after UL, the PN of some neurons resumed the network pattern as was observed in normal adult rats. This phenomenon was found in the PN of the remaining neurons by 14 days after UL. The PN on the labyrinth-intact side showed the compact network of uninjured age-matched rats. Taken together, our findings indicate PN changes that suggest possible correlation with vestibular nuclear neuronal function both during postnatal development of normal rats as well as in adult rats following destruction of the ipsilateral inner ear.