The expression changes of Numblike in rat brain cortex after traumatic brain injury

Numblike (Numbl) plays an important role in ependymal wall integrity and subventricular zone neuroblast survival. And Numbl is specifically expressed in the brain. However, its expression and function in the central nervous system lesion are still unclear. In this study, we performed a traumatic brain injury (TBI) model in adult rats and investigated the dynamic changes of Numbl expression in the brain cortex. Western blot and immunohistochemistry analysis revealed that Numbl was present in normal brain. It gradually decreased, reached the lowest point at day 3 after TBI, and then increased during the following days. Double immunofluorescence staining showed that Numbl immunoreactivity was found in neurons, but not astrocytes and microglia. Moreover, the 3rd day post injury was the apoptotic peak implied by the alteration of caspase-3. All these results suggested that Numbl may be involved in the pathophysiology of TBI and further research is needed to have a good understanding of its function and mechanism.