Neuroprotective effect of AG490 in experimental traumatic brain injury of rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Traumatic brain injury (TBI) is a major cause of death and disability in children and young adults worldwide. Therefore, we investigated the role of AG490 in regulating brain oedema, expression of CD40 and neurological function after TBI.</p><p><b>METHODS</b>Sprague Dawley rats (n = 240) were randomly divided into a sham operation group, TBI+saline group and TBI+AG490 (JAK/STAT inhibitor) group. Members of each group were euthanized at 6, 12, 24 or 72 hours after injury. Neurological severity score (NSS) was used to evaluate the severity of neurological damage. Brain water was quantitated by wet/dry weight method. The expression of CD40 was assessed by flow cytometry.</p><p><b>RESULTS</b>In both the TBI+saline group and the TBI+AG490 group, the brain water content was elevated after TBI, reached a peak at 24-hour and remained high for the rest of the period investigated; the expression of CD40 reached a peak 24 hours after TBI; the NSS was elevated after TBI and then decreased after 6 hours. Elevations in the level of CD40, degree of brain edema and NSS after TBI were significantly reduced in TBI+AG490 group.</p><p><b>CONCLUSION</b>Inhibition of the JAK/STAT signalling pathway reduces brain oedema, decreases the expression of CD40 and exerts neuroprotective effects after TBI.</p>

Activation of c-Jun N-terminal kinase 1/2 regulated by nitric oxide is associated with neuronal survival in hippocampal neurons in a rat model of ischemia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>C-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in cerebral ischemia. Although the mechanistic basis for this activation of JNK1/2 is uncertain, oxidative stress may play a role. The purpose of this study was to investigate whether the activation of JNK1/2 is associated with the production of endogenous nitric oxide (NO).</p><p><b>METHODS</b>Ischemia and reperfusion (I/R) was induced by cerebral four-vessel occlusion. Sprague-Dawley (SD) rats were divided into 6 groups: sham group, I/R group, neuronal nitric oxide synthase (nNOS) inhibitor (7-nitroindazole, 7-NI) given group, inducible nitric oxide synthase (iNOS) inhibitor (2-amino-5,6-dihydro-methylthiazine, AMT) given group, sodium chloride control group, and 1% dimethyl sulfoxide (DMSO) control group. The levels of protein expression and phospho-JNK1/2 were detected by Western blotting and the survival hippocampus neurons in CA1 zone were observed by cresyl violet staining.</p><p><b>RESULTS</b>The study illustrated two peaks of JNK1/2 activation occurred at 30 minutes and 3 days during reperfusion. 7-NI inhibited JNK1/2 activation during the early reperfusion, whereas AMT preferably attenuated JNK1/2 activation during the later reperfusion. Administration of 7-NI and AMT can decrease I/R-induced neuronal loss in hippocampal CA1 region.</p><p><b>CONCLUSION</b>JNK1/2 activation is associated with endogenous NO in response to ischemic insult.</p>