Neuroprotective effect of triptolide on neuronal inflammation in rats with mild brain injury.

Concussions sustained while playing sports are a prominent cause of mild traumatic brain injury (mTBI), which is prevalent among teenagers. The early and intermediate stages of mild traumatic brain injury (mTBI) can be characterized by inflammation, neurodegeneration, and brain tissue edema, which can lead to permanent brain damage. The present study investigated the therapeutic effects of triptolide in mTBI and brain damage recovery. After building mTBI model in male rat, triptolide administrated daily for 1 week in the treated group. On day 3 and day 7 of administration, hippocampus tissues were collected to evaluate inflammation and autophagy in the brain. The expressions of inflammatory factors interleukin (IL)-1ß and tumor necrosis factor-alpha in serum were downregulated, while IL-10 expression was upregulated when compared with the mTBI group on day 3 and day 7. The expression of IL-10 on day 7 was higher than on day 3. Quantitative polymerase chain reaction (qPCR) analysis of inflammatory-related factors (i.e., Il-1ß and nuclear factor-κB (Nf-κb), and western blot as well as immunofluorescence staining of autophagy-related proteins (i.e., LC3B) and aquaporin (AQP 4) showed lower expression on day 3 and day 7 in the triptolide-treated group. Moreover, NeuN immunostaining, and hematoxylin and eosin (HE) staining for hippocampus region revealed that the triptolide-treated group showed a decrease in damaged cells. Our findings emphasize the effectiveness of triptolide therapy after mild traumatic brain injury via modulating autophagy, attenuating inflammation and reduces edema by decreasing AQP 4 expression.

Thymoquinone regulates microglial M1/M2 polarization after cerebral ischemia-reperfusion injury via the TLR4 signaling pathway.

Acute ischemic stroke followed by microglia activation, and the regulation of neuroinflammatory responses after ischemic injury involves microglia polarization. microglia polarization is involved in the regulation of neuroinflammatory responses and ischemic stroke-related brain damage. Thymoquinone (TQ) is an anti-inflammatory agent following ischemic stroke onset. However, the significance of TQ in microglia polarization following acute ischemic stroke is still unclear. We predicted that TQ might have neuroprotective properties by modulating microglia polarization. In this work, we mimicked the clinical signs of acute ischemic stroke using a mouse middle cerebral artery ischemia-reperfusion (I/R) model. It was discovered that TQ treatment decreased I/R-induced infarct volume, cerebral oedema, and promoted neuronal survival, as well as improved the histopathological changes of brain tissue. The sensorimotor function was assessed by the Garica score, foot fault test, and corner test, and it was found that TQ could improve the motor deficits caused by I/R. Secondly, real-time fluorescence quantitative PCR, immuno-fluorescence, ELISA, and western blot were used to detect the expression of M1/M2-specific markers in microglia to explore the role of TQ in the modulation of microglial cell polarization after cerebral ischemia-reperfusion. We found that TQ was able to promote the polarization of microglia with extremely secreted inflammatory factors from M1 type to M2 type. Furthermore, TQ could block the TLR4/NF-κB signaling pathway via Hif-1α activation which subsequently may attenuate microglia differentiation following the cerebral ischemia, establishing a mechanism for the TQ's beneficial effects in the cerebral ischemia-reperfusion model.

Edaravone dexborneol alleviates cerebral ischemia-reperfusion injury through NF-κB/NLRP3 signal pathway.

Inflammatory injury following ischemia-reperfusion (I/R) severely limits the efficacy of stroke treatment. Edaravone dexborneol (C.EDA) has been shown to reduce inflammation following a cerebral hemorrhage. However, the precise anti-inflammatory mechanism of C.EDA is unknown. In this study, we investigated whether C.EDA provides neuroprotection after I/R in rats, as well as the potential mechanisms involved. A middle cerebral artery occlusion/reperfusion (I/R) model was created using Sprague-Dawley rats. The blood flow of the central cerebral artery was monitored by a laser speckle imaging system. The neurological score was used to assess behavioral improvement. Cerebral infarction volume was measured by TTC staining. And the integrity of the blood-brain barrier was detected by Evan's blue staining. The expression of the nuclear factor kappa-B (NF-κB)/ the NOD-like receptor protein (NLRP3) inflammasome signal pathway and microglia polarization were detected by immunofluorescence and Western blotting. The cerebral blood flow ratio indicates that the cerebral I/R model was successfully established. After reperfusion for 72 h, the improvement of neurological scores, infarct volume reduction, and integrity of the blood-brain barrier was observed in I/R rats with C.EDA treatment. Meanwhile, the immunofluorescence result showed that the expression of iNOS, NLRP3, and NF-κB protein was decreased and the level of Arg1 was increased. Western blot analysis showed that the expression of NF-κB/NLRP3 signal pathway-related protein was decreased. In conclusion, this study indicates that C.EDA alleviates I/R injury by blocking the activation of the NLRP3 inflammasome and regulating the polarization of M1/M2 microglia via the NF-κB signal pathway.

Effects of Neuroinflammation and Autophagy on the Structure of the Blood-Brain Barrier in ADHD Model.

Spontaneously hypertensive rats (SHR) are the most common animal model used to study attention deficit hyperactivity disorder (ADHD). The purpose of this study was to look at the impact of neuroinflammation and autophagy on blood-brain barrier function in the prefrontal cortex and hippocampus of ADHD rats. The rats were separated into three groups: juvenile SHR (6 weeks), mature SHR (12 weeks), and comparable age WKY groups. An open-field test was used to assess rats' ability to move on their own. Immunofluorescence was used to detect the Iba1-immunopositive microglia, ZO-1 and TNF-α. Meanwhile, the expression of p62, Beclin-1, LC3B, and MMP9, MMP2, TNF-α, ZO-1, and occludin were detected by Western blot. The results have shown that Iba1-immunopositive microglia and TNF-α protein in the brain of SHR rats were significantly increased. Moreover, autophagy of cells and the level of MMP2 and MPP9 in the prefrontal cortex and hippocampus increased in SHR rats. In addition, the expression of ZO-1 and occludin was decreased in SHR rats. To sum up, the increase of neuroinflammation and excessive autophagy were essential factors for the damage of blood-brain barrier structure and function.

Upregulations of high mobility group box 1 and TLR4/NF-κB signaling pathway in hippocampus and serum of rats with febrile seizure.

PURPOSE: The aim of this study was to explore the alternations regarding the HMGB1 and TLR4/NF-κB signaling pathway in juvenile rats with febrile seizure (FS). MATERIALS AND METHODS: During the animal modeling of the FS, seizures were triggered every four days by hot water (45 °C), and repeated ten times. After forty days' modeling, rats were divided into different groups according to the degree of seizure (FS (0) - FS (V)). Reverse transcription-polymerase chain reaction (RT-PCR) was used to evaluate the mRNA expressions of the HMGB1, TLR4 and NF-κB in the hippocampus, while Western-blot (WB) and immunofluorescence (IF) were employed to assess protein expressions. The enzyme-linked immunosorbent assay (ELISA) was used for analyzing the protein expressions in peripheral blood. RESULTS: The mRNA levels of the HMGB1, TLR4 and NF-κB in the hippocampus of both FS (V) and FS (IV) groups were significantly higher than WT, while there was no difference between FS (III) and WT. Concerning protein expressions, increased levels of the HMGB1, TLR4, and NF-κB in FS (V) were observed with a good consistency between the WB and IF, while no significant upregulation was shown in FS (IV). The ELISA results showed that the significance of the augmented proteins between the FS (V) and WT were smaller in the serum than the hippocampus. CONCLUSIONS: Our study shows seizure degree-related upregulations of HMGB1 and TLR4/NF-κB signaling pathway both in hippocampus and serum of juvenile rats with FS, suggesting the involvement of TLR/NF-κB pathway in inflammation promoted by HMGB1 during FS.

Quercetin alleviates subarachnoid hemorrhage-induced early brain injury via inhibiting ferroptosis in the rat model.

Early brain injury (EBI) refers to a series of pathophysiological brain lesions that occur within 72 hr after subarachnoid hemorrhage (SAH), which is an extremely crucial factor in the poor prognosis of patients. In EBI, ferroptosis has been proven to cause neuronal death. Quercetin (QCT) is effective in deactivating reactive oxygen species (ROS), inhibiting lipid peroxidation, and even chelating iron, but its role in SAH remains unclear. In this study, the mortality rate, severity grade of SAH, brain water content (BWC), blood-brain barrier permeability, and neurological function of the rats were detected. Moreover, mitochondrial morphology in cortical neurons were observed and their sizes were subsequently quantified. The levels of lipid peroxidation on glutathione and malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were determined, whereas the protein expressions of glutathione peroxidase 4 (GPX4), SLC7A11 (xCT), transferrin receptor 1 (TfR1), and ferroportin-1 (FPN1) were analyzed by western immunoblotting. The neurodegeneration involved in EBI was investigated by fluoro-Jade C staining, while iron staining was utilized to measure iron content. Our results showed that inhibition of ferroptosis by QCT could suppress EBI and improve neurological function in SAH rats. QCT increased the expression levels of GPX4, xCT, and FPN1, while downregulated TfR1, and exerted protective effects on neurons as well as alleviated iron accumulation and lipid peroxidation in the cortex of SAH rats. In conclusion, our study revealed that QCT might alleviate the EBI by inhibiting ferroptosis in SAH rats.

Enhanced Glial Reaction and Altered Neuronal Nitric Oxide Synthase are Implicated in Attention Deficit Hyperactivity Disorder.

Attention deficit hyperactivity disorder (ADHD) has a complex etiology, and its specific causal factors remain to be elucidated. Aberration of nitric oxide synthase (nNOS) and inflammation, together with astrocytic and microglial cells have been continually associated with several neurological disorders, including ADHD. Using spontaneously hypertensive rat (SHR), we investigated the changes in nNOS, inflammatory, microglial and astrocytic markers in the frontal cortex and hippocampus at three different ages: onset of hypertension stage (i.e., 6 weeks after birth of SHR), established hypertension stage (i.e., 12 weeks after birth of SHR) and senescent stage (i.e., 12 months after birth of SHR), and compared with its age-matched normotensive control, Wistar-Kyoto (WKY) rats. A significant upregulation of Iba-1 expression in the senescent stage of SHR was observed. Further, we observed an upregulated nNOS expression in both onset and established stages of SHR, and a downregulated nNOS in the senescent stage. Our study showed an age-related increment of astrogliosis in the cortex and hippocampi of aged SHR. On the basis of our results, alterations in the nNOS and Iba-1 expressions, as well as age-related astrogliosis, may contribute to ADHD pathogenesis.