engleski

Single moderate traumatic brain injury in mice causes changes in PSD-95 immunoreactivity in the ipsilateral cortex and hippocampus

Traumatic brain injury (TBI) is the leading cause of death and disability which mostly affects young, workable individuals. TBI survivors suffer from learning, memory and concentration deficits due to significant cell loss, axonal degeneration and loss of synapses. Postsynaptic density protein 95 (PSD-95) is a scaffolding protein that has a major role in synaptic plasticity. This study aimed to investigate the temporal pattern of PSD-95 immunoreactivity in ipsilateral and contralateral parietal cortices and hippocampi during the first 14 days after experimental TBI. Lateral fluid percussion injury of moderate severity was induced over the left parietal cortex of adult male C57BL/6 mice. Animals were sacrificed 1, 3 or 14 days after injury and their cortices and hippocampi were prepared for western blot analyses. Brains from another cohort of mice were prepared for immunohistological analyses. Sham-injured animals, used as the control group, were sacrificed 1 day after the sham procedure. A significant decrease of PSD-95 protein levels in the ipsilateral cortex was evident from day 1 until day 14 after trauma. Double immunofluorescence showed an evident decrease in neuron-specific marker NeuN as well as the loss of PSD-95. In the ipsilateral hippocampus, upregulation of PSD-95 was observed on the day 14 after TBI regarding sham-injured mice as well as the TBI mice sacrificed 1 and 3 days after trauma. Significant changes in the contralateral cortex and the hippocampus were not observed. Our preliminary results showed that the cortical levels of PSD-95 are reduced ipsilaterally during the first 14 days after trauma which suggests prolonged synaptic dysfunction in the injured cortex. Upregulation of PSD-95 in the ipsilateral hippocampus points to the presence of synaptic changes in this brain structure. This work was supported by the University of Rijeka, Croatia, project numbers uniri-biomed- 18-199 to K.P and 13.06.1.1.09 to GŽ.

Cortex, hippocampus, mouse, postsynaptic density protein 95, traumatic brain injury

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