Brain research
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Reliable animal models of traumatic brain injury (TBI) are essential to test novel hypotheses and therapeutic interventions. In this study, based on advantages of both the closed head injury (CHI) and controlled cortical impact (CCI) models, we developed a bilateral head injury model in mice. C57BL/6 mice were used in this study. ⋯ Furthermore, an adhesive removal test revealed significant increases in time-to-contact and time-to-remove the adhesive tape from the paw in a severity-dependent manner, indicating that our TBI model produced graded somatosensory and motor deficits. Histological analysis presented a clear gradation in brain tissue damage following graded brain injuries. These findings collectively suggest that the current model may offer a sensitive, reliable and clinically-relevant model for assessments of therapeutic strategies forTBI.
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Repetitive mild traumatic brain injury (rmTBI) is an important medical concern for active sports and military personnel. Multiple mild injuries may exacerbate tissue damage resulting in cumulative brain injury and poor functional recovery. In the present study, we investigated the time course of brain vulnerability to rmTBI in a rat model of mild cortical controlled impact. ⋯ There were no neurological deficits associated with rmTBI 3 day animals. At 1 mo post-injury, animals with rmTBI 3 days apart showed reduced exploratory behaviors and subtle spatial learning memory impairments were observed. Collectively, our findings suggest that the mildly-impacted brain is more vulnerable to repetitive injury when delivered within 3 days following initial mTBI.
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Paeoniflorin is a monoterpene glycoside isolated from the aqueous extract of the dry root of Paeonia. It has been identified to exhibit many pharmacological effects including enhancing the cognitive ability, producing anti-depressant-like effect and reducing the MTPT-induced toxicity. In our previous study, it has shown that paeoniflorin improved the cognitive ability and attenuated the oxidative stress in the Aβ(1-42)-treated rats. ⋯ The results showed that the long-term treatment of paeoniflorin or donepezil enhanced the cognitive performances in the Morris water maze test, restored the decreased activities of superoxide dismutase and catalase and the increased level of malondialdehyde, and reversed the alterations of matrix metallopeptidase-9 and tissue-inhibitor of metalloproteinase-1 in the hippocampus of Aβ(1-42)-treated rats. Paeoniflorin also up-regulated the activity of choline acetyltrasferase and the expression of tyrosine kinase A receptor, and down-regulated the activity of acetylcholine esterase in the hippocampus of Aβ(1-42)-treated rats. These results demonstrate that paeoniflorin ameliorates the spatial learning and memory deficits by attenuating oxidative stress and regulating the nerve growth factor-mediated signaling to reinforce cholinergic functions in the hippocampus of the Aβ(1-42)-treated rats.