International Congress of the Polish Neuroscience Society edition:9 location:Warsaw, Poland date:9-12 September 2009
Thymosin beta 4 (Tβ4) is a peptide of 43 amino acids, mainly recognized as a regulator of actin polymerisation by sequestering G-actin. The peptide has been implicated in apoptosis, angiogenesis and lesion-induced neuroplasticity. Tβ4 is widely distributed in the brain, in neurons as well as in microglia. In this study we examined possible changes in Tβ4 expression in the visual system of the mouse after surgical removal of one eye. Adult mice were deprived of vision and sacrificed 1, 3 and 5 days and 1, 2 and 7 weeks after enucleation of the right eye. After 3 days of monocular deprivation, a substantial up-regulation of Tβ4-positive microglia was visible in the left superior colliculus, which faded with post-lesion survival time. The Tβ4-positive microglia appeared activated for clearance of debris of degenerating axons and myelin. Apart from this microglial activation, a remarkable neuronal response was observed. In the deeper layers of the left and right superior colliculus Tβ4-positive neurons with very long Tβ4-positive neurites became apparent. These cells were visible within 1 week but became more obvious 7 weeks post-lesion. Tβ4 may therefore participate in growth or remodeling of neuronal processes in deep layers of the superior colliculus possibly to induce some form of recovery of the visual system upon sensory deprivation.