Electroacupuncture regulates microglial polarization via inhibiting NF-κB/COX2 pathway following traumatic brain injury.

BACKGROUND: Neuroinflammation and oxidative stress are important pathological mechanisms following traumatic brain injury (TBI). The NF-κB/COX2 pathway regulates neuroinflammation and oxidative damage, while microglia also play an important role in neuroinflammation. Since NF-κB is involved in microglial polarization, targeting this pathway and microglial polarization is a critical component of TBI treatment. Currently, electroacupuncture (EA) is widely used to treat various symptoms after TBI, but the mechanisms of EA remain poorly understood. Additionally, the optimal frequency of EA remains unclear, which affects its efficacy. This study focuses on exploring the optimal frequency parameters of EA on TBI and investigating the underlying mechanisms of EA through NF-κB/COX2 pathway and microglial polarization. METHODS: The study was divided into two parts. In Experiment 1, 42 Sprague Dawley (SD) rats were induced and randomly divided into seven groups (n = 6). Except for the sham group, all rats underwent controlled cortical impact (CCI) to establish TBI model. Four EA groups (with different frequencies) and manual acupuncture (without current stimulation) received stimulation on the acupoints of Shuigou (GV26), Fengchi (GB20) and Neiguan (PC6) once a day for 7 days. The neurological function was assessed by modified Neurological Severity Scores (mNSS), and the rats' memory and learning were examined by the Morris water maze (MWM). SOD, MDA, and GSH-Px were detected to evaluate the levels of oxidative stress. The levels of IL-1ß, IL-6, and TNF-α were evaluated by Enzyme Linked Immunosorbent Assay (ELISA). Detection of the above indicators indicated a treatment group that exerted the strongest neuroprotection against TBI, we then conducted Experiment 2 using this screened acupuncture treatment to investigate the mechanism of acupuncture. 48 rats were randomly divided into four groups (n = 12): sham, TBI model, acupuncture and PDTC (NF-κB inhibitor). Evaluations of mNSS, MWM test, SOD, MDA, GSH-Px, IL-1ß, IL-6, TNF-α, and IL-10 were the same as in Experiment 1. Western blot was applied for detecting the expression levels of NF-κB, p-NF-κB, COX2, and Arg-1. TUNEL was used to examine neuronal apoptosis. Brain structure was observed by H&E. Iba-1, COX2, and Arg-1 were investigated by immunofluorescence staining. RESULTS: EA with frequency of 2/100 Hz markedly improved neuronal and cognitive function as compared to the other treatment groups. Moreover, it downregulated the expression of MDA, IL-6, IL-1ß, and TNF-α and upregulated the levels of SOD and GSH-Px. In addition, Both EA with 2/100 Hz and PDTC reduced the levels of p-NF-κB, COX2 and M1 markers (COX2, IL-6, IL-1ß, TNF-α) and increased the levels of M2 markers (Arg-1, IL-10). Moreover, they had similar effects on reducing inflammation, oxidative stress and apoptosis, and improving neuronal and cognitive function. CONCLUSIONS: The collective findings strongly suggest that EA with 2/100 Hz can improve neurologic function by suppressing neuroinflammation, oxidative stress and apoptosis. Additionally, we confirm that EA promotes microglial polarization towards the M2 phenotype through the suppression of NF-κB/COX2 pathway, thus exerting neuroprotective effects after TBI.

N6-methyladenosine profiling reveals that Xuefu Zhuyu decoction upregulates METTL14 and BDNF in a rat model of traumatic brain injury.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Chinese herbal formula Xuefu Zhuyu decoction (XFZYD) is a classic formula in the category of invigorating blood circulation and resolving blood stasis. It has been proven to improve the neurological and ethological prognosis of traumatic brain injury. XFZYD promotes synaptic and axonal regeneration after traumatic brain injury, which is functionally modulated by the N6-methyladenosine (m6A) modification of RNA. However, the epigenetic effects of XFZYD on m6A modification remain unknown. AIM OF THE STUDY: To explore how XFZYD protects against traumatic brain injury induced by controlled cortical impact (CCI) injury by altering RNA m6A modification. MATERIALS AND METHODS: The modified neurological severity scoring and Morris water maze were performed to evaluate the neuroprotective effects of XFZYD for 14 days and screen the dose. Then, dot blot, western blotting, and methylated RNA immunoprecipitation sequencing (MeRIP-Seq) were used to explore changes in RNA m6A modification in the perilesional cortex. The Metascape platform was used to analyze the Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway of the differential m6A-tagged genes. Furthermore, MeRIP-qPCR was conducted to quantify differences in the hub differential m6A modification gene brain-derived neurotrophic factor (Bdnf). RESULTS: XFZYD significantly ameliorated the neurological deficits, spatial learning, and memory impairments in rats post-CCI on day 14. XFZYD enhanced the m6A level, and the expression of METTL14 and YTHDC2 in the perilesional cortex of CCI rats. In all three groups, the 3'-untranslated regions and coding sequence were primarily enriched for m6A peaks. XFZYD reversed the increased proportion of 3'-untranslated regions, and the decreased proportion of coding sequence and 5'-untranslated regions post-CCI. Moreover, XFZYD markedly downregulated 41 elevated m6A-tagged transcripts and upregulated 119 decreased m6A-tagged transcripts following CCI. Gene ontology and KEGG pathway analysis revealed that XFZYD-regulated m6A-tagged transcripts were predominantly enriched in synapse assembly, synaptic plasticity, learning or memory, and MAPK signaling pathway. Then, the hub-regulated m6A-tagged gene BDNF was identified. Both the m6A methylation level and the protein level of BDNF were ascended by XFZYD treatment. CONCLUSION: XFZYD improves neurological deficits, spatial learning and memory impairments in rats post-TBI probably through increasing the expression of METTL14 and BDNF in the cortex. Our study highlights a novel post-transcriptional regulation mechanism mediated by herbal medicine for traumatic brain injury treatment.

Deletion of glutamate carboxypeptidase II (GCPII), but not GCPIII, provided long-term benefits in mice with traumatic brain injury.

MAIN PROBLEM: N-acetylaspartylglutamate (NAAG) has neuroprotective effects in traumatic brain injury (TBI) by activating metabotropic glutamate receptor 3 (mGluR3) and reducing glutamate release. Glutamate carboxypeptidase II (GCPII) is the primary enzyme responsible for the hydrolysis of NAAG. It remains unclear whether glutamate carboxypeptidase III (GCPIII), a homolog of GCPII, can partially compensate for GCPII's function. METHODS: GCPII-/- , GCPIII-/- , and GCPII/III-/- mice were generated using CRISPR/Cas9 technology. Mice brain injury model was established through moderate controlled cortical impact (CCI). The relationship between GCPII and GCPIII was explored by analyzing injury response signals in the hippocampus and cortex of mice with different genotypes at the acute (1 day) and subacute (7 day) phase after TBI. RESULTS: In this study, we found that deletion of GCPII reduced glutamate production, excitotoxicity, and neuronal damage and improved cognitive function, but GCPIII deletion had no significant neuroprotective effect. Additionally, there was no significant difference in the neuroprotective effect between the combination of GCPII and GCPIII deletion and GCPII deletion alone. CONCLUSION: These results suggest that GCPII inhibition may be a therapeutic option for TBI, and that GCPIII may not act as a complementary enzyme to GCPII in this context.

[Effects of electroacupuncture on neurological function and expressions of p-JNK and Beclin-1 in traumatic brain injury rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on neurological function, the expressions of phosphorylated c-Jun amino terminal kinase (p-JNK) and Beclin-1 in rats with traumatic brain injury (TBI), so as to explore the underlying mechanism of EA in the treatment of TBI. METHODS: A total of 64 SD rats were randomly divided into blank, sham, modeling groups, with 8 rats in the blank group and the sham group and 48 rats in the modeling group. The modified Feeney free-fall impact method was used to establish the TBI rat model. After modeling, rats of the modeling group were randomly divided into model and EA groups, which were further divided into 3 d, 7 d and 14 d subgroups with 8 rats in each group. Rats in the EA group were treated with acupuncture at "Baihui" (GV20, retained for 15 min), "Shuigou" (GV26, stabbed for 20 s), "Neiguan" (PC6) and "Zusanli" (ST36) of the right side. EA (2 Hz, 1 mA) was applied to PC6 and ST36 for 15 min. The above treatments were performed once a day, and different subgroups were continuously stimulated for 3, 7 and 14 days, respectively. The neurological impairment was evaluated by modified neurological severity score(mNSS). The pathological morphological changes and the protein expressions of p-JNK and Beclin-1 in the injured area of the brain were detected by Nissl staining and immunohistochemistry, separately. RESULTS: After modeling, the mNSS and the protein expressions of p-JNK and Beclin-1 were increased (P< 0.05) on day 3, 7 and 14 in the model group relative to the sham group. The Nissl bodies were reduced or even dissolved and neurons were seriously damaged in the model group on the 3rd day, which were mildly repaired on day 7 and 14. Following acupuncture interventions, compared with the model group, the mNSS on day 7 and 14 and the protein expressions of p-JNK and Beclin-1 on day 3, 7 and 14 were decreased (P< 0.05)in the EA group. The status of Nissl bodies and neurons in the EA group was better at all time points than that in the model group. There were no significant differences in the above indicators between the blank group and the sham group. CONCLUSION: EA can significantly improve the neurological function of TBI model rats, which may be related to its effects in down-regulating the protein expressions of p-JNK and Beclin-1 in the injured area of the brain.

Effects of acupuncture on microglial polarization and the TLR4/TRIF/MyD88 pathway in a rat model of traumatic brain injury.

OBJECTIVE: Neuroinflammation caused by traumatic brain injury (TBI) can lead to neurological deficits. Acupuncture can inhibit neuroinflammation and promote nerve repair; however, the specific mechanism is still unclear. The purpose of this study was to explore whether acupuncture could modulate the M1 and M2 phenotypic polarization of microglia in a rat model of TBI via the toll-like receptor 4 (TLR4)/intracellular toll-interleukin-1 receptor (TIR) domain-containing adaptor inducing interferon-ß (TRIF)/myeloid differentiation factor 88 (MyD88) pathway. METHODS: A total of 90 adult male Sprague-Dawley (SD) rats, SPF grade, were randomly divided into a normal group, model group and acupuncture group. Each group was further divided into three subgroups (first, third, and fifth day groups) according to the treatment time (n = 10 rats/subgroup). We used the modified neurological severity score (mNSS) method to quantify neurological deficits before and after modeling. We used Nissl staining to observe the pathological changes in brain tissue, flow cytometry to detect the proportion of M1 and M2 polarized microglia in the injured area on the first, third and fifth day, and co-immunoprecipitation (Co-IP) to examine TLR4/TRIF/MyD88 expression in microglia on the first, third and fifth day, as well as expression of the amount of binding of TLR4 with TRIF and MyD88. RESULTS: Compared to the model group, mNSS in the acupuncture group gradually decreased and pathological morphology improved. The proportion of CD11b/CD86 positive cells was decreased, while that of CD11b/CD206 was increased in the acupuncture group. Expression of IP TLR4, IP TRIF and IP MyD88 also decreased in the acupuncture group. CONCLUSION: The results of this study demonstrate that one of the mechanisms through which acupuncture mitigates neuroinflammation and promotes nerve repair in TBI rats may be inhibition of M1 phenotypic polarization and promotion of M2 phenotypic polarization through inhibition of the TLR4/TRIF/MyD88 signaling pathway.

The role of salivary vesicles as a potential inflammatory biomarker to detect traumatic brain injury in mixed martial artists.

Traumatic brain injury (TBI) is of significant concern in the realm of high impact contact sports, including mixed martial arts (MMA). Extracellular vesicles (EVs) travel between the brain and oral cavity and may be isolated from salivary samples as a noninvasive biomarker of TBI. Salivary EVs may highlight acute neurocognitive or neuropathological changes, which may be particularly useful as a biomarker in high impact sports. Pre and post-fight samples of saliva were isolated from 8 MMA fighters and 7 from controls. Real-time PCR of salivary EVs was done using the TaqMan Human Inflammatory array. Gene expression profiles were compared pre-fight to post-fight as well as pre-fight to controls. Largest signals were noted for fighters sustaining a loss by technical knockout (higher impact mechanism of injury) or a full match culminating in referee decision (longer length of fight), while smaller signals were noted for fighters winning by joint or choke submission (lower impact mechanism as well as less time). A correlation was observed between absolute gene information signals and fight related markers of head injury severity. Gene expression was also significantly different in MMA fighters pre-fight compared to controls. Our findings suggest that salivary EVs as a potential biomarker in the acute period following head injury to identify injury severity and can help elucidate pathophysiological processes involved in TBI.

Initiators of Classical and Lectin Complement Pathways Are Differently Engaged after Traumatic Brain Injury-Time-Dependent Changes in the Cortex, Striatum, Thalamus and Hippocampus in a Mouse Model.

The complement system is involved in promoting secondary injury after traumatic brain injury (TBI), but the roles of the classical and lectin pathways leading to complement activation need to be clarified. To this end, we aimed to determine the ability of the brain to activate the synthesis of classical and lectin pathway initiators in response to TBI and to examine their expression in primary microglial cell cultures. We have modeled TBI in mice by controlled cortical impact (CCI), a clinically relevant experimental model. Using Real-time quantitative polymerase chain reaction (RT-qPCR) we analyzed the expression of initiators of classical the complement component 1q, 1r and 1s (C1q, C1r, and C1s) and lectin (mannose binding lectin A, mannose binding lectin C, collectin 11, ficolin A, and ficolin B) complement pathways and other cellular markers in four brain areas (cortex, striatum, thalamus and hippocampus) of mice exposed to CCI from 24 h and up to 5 weeks. In all murine ipsilateral brain structures assessed, we detected long-lasting, time- and area-dependent significant increases in the mRNA levels of all classical (C1q, C1s, C1r) and some lectin (collectin 11, ficolin A, ficolin B) initiator molecules after TBI. In parallel, we observed significantly enhanced expression of cellular markers for neutrophils (Cd177), T cells (Cd8), astrocytes (glial fibrillary acidic protein-GFAP), microglia/macrophages (allograft inflammatory factor 1-IBA-1), and microglia (transmembrane protein 119-TMEM119); moreover, we detected astrocytes (GFAP) and microglia/macrophages (IBA-1) protein level strong upregulation in all analyzed brain areas. Further, the results obtained in primary microglial cell cultures suggested that these cells may be largely responsible for the biosynthesis of classical pathway initiators. However, microglia are unlikely to be responsible for the production of the lectin pathway initiators. Immunofluorescence analysis confirmed that at the site of brain injury, the C1q is localized in microglia/macrophages and neurons but not in astroglial cells. In sum, the brain strongly reacts to TBI by activating the local synthesis of classical and lectin complement pathway activators. Thus, the brain responds to TBI with a strong, widespread and persistent upregulation of complement components, the targeting of which may provide protection in TBI.

[Effect of electroacupuncture at different stages on the expression of Fas and FasL in brain tissue of rats with traumatic brain injury].

OBJECTIVE: To investigate the expression of apoptosis-related proteins Fas and FasL in the brain tissue of rats with traumatic brain injury and the effect of electroacupuncture on the expression of Fas and FasL, so as to explore the effective time window of electroacupuncture in the treatment of traumatic brain injury. METHODS: Sprague-Dawley rats were randomly divided into blank group, sham-operation group, model group, and electroacupuncture treatment groups 1, 2, and 3. Traumatic brain injury was induced by the modified Feeney free-fall impact device, and for the rats in the electroacupuncture treatment groups 1, 2, and 3, electroacupuncture started at 4 hours and on days 3 and 7, respectively, after modeling and lasted to day 14. The Morris water maze test was used to evaluate learning and memory ability, and immunofluorescence assay and Western blot were used to observe the changes in the expression of Fas and FasL in traumatic brain tissue. RESULTS: Compared with the blank group and the sham-operation group, the model group had a lower percentage of time spent in the target quadrant from the 3rd day folowing modeling; after electroacupuncture intervention, the electroacupuncture treatment groups showed a gradual increase in the time spent in the target quadrant, and on day 7,10 and 14, electroacupuncture treatment group 1 had a significantly higher percentage than the model group (P<0.05). On day 14, electroacupuncture treatment group 2 had a significantly higher percentage than the model group (P<0.05). After electroacupuncture intervention, all groups except the blank group and the sham-operation group had increases in the expression of Fas and FasL in brain tissue, which reached the highest level on day 7 after modeling and then tended to decrease; compared with electroacupuncture treatment groups 2 and 3 and the model group, electroacupuncture treatment group 1 had significant reductions in the expression of Fas and FasL (P<0.05, P<0.01); compared with electroacupuncture treatment group 3 and the model group, electroacupuncture treatment group 2 had significant decreases in the expression of Fas and FasL (P<0.05) on day 14 after modeling; compared with the model group, electroacupuncture treatment group 3 had significant reductions in the expression of Fas and FasL in brain tissue on day 14 after modeling (P<0.05). CONCLUSION: Early electroacupuncture intervention can regulate the apoptosis receptor pathway by down-regulating Fas and FasL to exert a therapeutic effect on traumatic brain injury and help with the recovery of cognition and memory ability after traumatic brain injury.

The effect of different atmosphere absolute hyperbaric oxygen on the expression of extracellular histones after traumatic brain injury in rats.

By observing the dynamic changes of extracellular histones H1, H2A, H4, and NF-κB expression in brain tissues after brain injury in rats, we explore the association among the expression of extracellular histones H1, H2A, H4, and NF-κB following traumatic brain injury (TBI), as well as the effect of different atmospheres absolute hyperbaric oxygen (HBO) intervention on the expression and possible mechanisms. A total of 120 SD rats were randomly divided into 4 groups: Sham-operated (SH), TBI (traumatic brain injury) group, traumatic brain injury and hyperbaric oxygen treatment 1.6ATA (TBI + HBO1) group, and traumatic brain injury and hyperbaric oxygen treatment2.2ATA (TBI + HBO2) group, with 30 rats in each group. The rats in each group were then randomly divided into five smaller time-specific sub-groups: 3 h, 6 h, 12 h, 24 h, and 48 h after surgery. TBI models were established, and the brain tissue around the lesion was taken at different time points. On the one hand,we detected the level of local histones H1, H2A, H4, and NF-κB by RT-PCR and Western Blot. On the other hand, we used immunohistochemical methods to detect the expression of NF-κB, while using the TUNEL method to observe the cell apoptosis in experimental groups after brain injury. Extracellular histones H1, H2A, H4, and NF-κB proteins were highly expressed at 3 h, then with a slight fluctuation, reached to peak at 48 h after the injury. HBO can affect the expression of histones H1, H2A, H4, and NF-κB. The decline of each indicator in the 1.6ATA group was significantly lower than that in the 2.2ATA group, especially within 6 h (P < 0. 05). In addition, NF-κB expression was consistent with the pathological changes of apoptosis in experimental groups. Hyperbaric oxygen therapy with relatively low pressure (1.6ATA) at the early stage can significantly inhibit the expression of extracellular histones H1, H2A, H4, and NF-κB around the lesion, reduce the apoptosis of nerve cells, and thus play an important role in alleviating secondary brain injury.

"Acupuncture stimulation of Yamen (GV 15), Fengfu (GV 16), Baihui (GV 20), Shuigou (GV 26) and Hegu (LI 4) reduces brain microglia activation in a traumatic brain injury rat model".

OBJECTIVE: To evaluate the effect of acupuncture on neuroinflammation in traumatic brain injury (TBI) rats by stimulating Yamen (GV 15), Fengfu (GV 16), Baihui (GV 20), Shuigou (GV 26) and Hegu (LI 4) acupoints and to investigate the mechanism underpinning this effect. METHODS: A TBI model was induced in Sprague- Dawley rats using Feeney's freefall impact method. Acupuncture to stimulate the Yamen (GV 15), Fengfu (GV 16), Baihui (GV 20), Shuigou (GV 26) and Hegu (LI 4) acupoints was performed on the TBI rats. After 3 consecutive days of acupuncture treatment, we investigated signal molecules, receptors and microglia related to neuroinflammation in brain tissue of the TBI rats and analyzed the possible mechanism underlying the effect of acupuncture on neuroinflammation. RESULTS: After the acupuncture treatment, ionized calcium binding adaptor molecule 1(Iba1), a protein specific to microglia, was investigated. In the cortical layer of damaged brain tissue in TBI rats, the Iba1-positive area was 3.3% ± 0.9% in the rats that received acupuncture compared with 5.2% ± 1.4% in the TBI rats that did not receive acupuncture, and the microglia were smaller with more slender protrusions in the acupuncture-treated rats. This result indicates that acupuncture can significantly reduce microglia activation in TBI rats. A possible mechanism for this effect is that acupuncture reduces the expression of autotaxin and lysophosphatidic acid. Together, these constitute the autotaxin-lysophosphatidic acid axis, which induces microglial activation in the brains of TBI rats. Acupuncture treatment may downregulate the expression of Lysophosphatidic acid (LPA) receptor (LPAR) 1 and LPAR2 on the microglial cytomembrane, which affects the microglia activation process. CONCLUSION: Acupuncture stimulating the Yamen (GV 15), Fengfu (GV 16), Baihui (GV 20), Shuigou (GV 26) and Hegu (LI 4) acupoints can effectively inhibit the development of neuroinflammation after TBI. One possible mechanism for this effect is that acupuncture downregulates LPA synthesis and affects the LPA-LPAR pathway by inhibiting LPAR1 and LPAR2, thereby inhibiting microglial activation and reducing neuroinflammation.

Manual acupuncture relieves microglia-mediated neuroinflammation in a rat model of traumatic brain injury by inhibiting the RhoA/ROCK2 pathway.

OBJECTIVE: To investigate the regulatory mechanism of manual acupuncture (MA) on microglial polarization-mediated neuroinflammation after traumatic brain injury (TBI), focusing on the RhoA/Rho-associated coiled coil-forming protein kinase (ROCK2) pathway. METHODS: Sprague Dawley (SD) rats were used to generate a TBI model using Feeney's freefall epidural impact method. MA was performed on half of the TBI model rats, while the others remained untreated. Acupuncture was administered at GV15, GV16, GV20, GV26, and LI4. At the end of the intervention, rat brain tissue samples were collected, and the microglial M1 polarization status was observed by immunofluorescence labeling of CD86, an M1 microglia-specific protein. RhoA/ROCK2 signaling components were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. An enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of inflammatory factors. RESULTS: Compared with normal rats, the CD86 expression density in the untreated TBI model rats was high and showed an aggregated expression pattern. The genes and proteins of the RhoA/ROCK2 signaling pathway were highly expressed, and inflammatory factors were significantly increased. The CD86 expression density in TBI rats after MA was reduced compared to that in untreated TBI rats and showed a scattered distribution. The expression of RhoA/ROCK2 signaling pathway genes and proteins was also significantly reduced, and inflammatory factors were decreased. CONCLUSION: These results show that MA may inhibit M1 polarization of microglia by regulating the RhoA/ROCK2 signaling pathway, thereby reducing neuroinflammation in TBI.

A Pilot Study Assessing the Impact of rs174537 on Circulating Polyunsaturated Fatty Acids and the Inflammatory Response in Patients with Traumatic Brain Injury.

Traumatic brain injury (TBI) is a leading cause of death and disability in persons under age 45. The hallmark secondary injury profile after TBI involves dynamic interactions between inflammatory and metabolic pathways including fatty acids. Omega-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) have been shown to provide neuroprotective benefits by minimizing neuroinflammation in rodents. These effects have been less conclusive in humans, however. We postulate genetic variants influencing PUFA metabolism in humans could contribute to these disparate findings. Therefore, we sought to (1) characterize the circulating PUFA response and (2) evaluate the impact of rs174537 on inflammation after TBI. A prospective, single-center, observational pilot study was conducted to collect blood samples from Level-1 trauma patients (N = 130) on admission and 24 h post-admission. Plasma was used to quantify PUFA levels and inflammatory cytokines. Deoxyribonucleic acid was extracted and genotyped at rs174537. Associations between PUFAs and inflammatory cytokines were analyzed for all trauma cases and stratified by race (Caucasians only), TBI (TBI: N = 47; non-TBI = 83) and rs174537 genotype (GG: N = 33, GT/TT: N = 44). Patients with TBI had higher plasma DHA levels compared with non-TBI at 24 h post-injury (p = 0.013). The SNP rs174537 was associated with both PUFA levels and inflammatory cytokines (p < 0.05). Specifically, TBI patients with GG genotype exhibited the highest plasma levels of DHA (1.33%) and interleukin-8 (121.5 ± 43.3 pg/mL), which were in turn associated with poorer outcomes. These data illustrate the impact of rs174537 on the post-TBI response. Further work is needed to ascertain how this genetic variant directly influences inflammation after trauma.

Dynamics of clusterin protein expression in the brain and plasma following experimental traumatic brain injury.

Progress in the preclinical and clinical development of neuroprotective and antiepileptogenic treatments for traumatic brain injury (TBI) necessitates the discovery of prognostic biomarkers for post-injury outcome. Our previous mRNA-seq data revealed a 1.8-2.5 fold increase in clusterin mRNA expression in lesioned brain areas in rats with lateral fluid-percussion injury (FPI)-induced TBI. On this basis, we hypothesized that TBI leads to increases in the brain levels of clusterin protein, and consequently, increased plasma clusterin levels. For evaluation, we induced TBI in adult male Sprague-Dawley rats (n = 80) by lateral FPI. We validated our mRNA-seq findings with RT-qPCR, confirming increased clusterin mRNA levels in the perilesional cortex (FC 3.3, p < 0.01) and ipsilateral thalamus (FC 2.4, p < 0.05) at 3 months post-TBI. Immunohistochemistry revealed a marked increase in extracellular clusterin protein expression in the perilesional cortex and ipsilateral hippocampus (7d to 1 month post-TBI), and ipsilateral thalamus (14d to 12 months post-TBI). In the thalamus, punctate immunoreactivity was most intense around activated microglia and mitochondria. Enzyme-linked immunoassays indicated that an acute 15% reduction, rather than an increase in plasma clusterin levels differentiated animals with TBI from sham-operated controls (AUC 0.851, p < 0.05). Our findings suggest that plasma clusterin is a candidate biomarker for acute TBI diagnosis.

Genotype and Injury Effect on the Expression of a Novel Hypothalamic Protein Sushi Repeat-Containing Protein X-Linked 2 (SRPX2).

Sushi repeat-containing protein X-linked 2 (SRPX2) is a novel hypothalamic protein and a ligand of the urokinase-type plasminogen activator receptor (uPAR), which is essential for proteolysis of extracellular matrix and tissue remodeling after an insult to the brain. However, little is known about regulation of SRPX2. Our objective was to investigate if SRPX2 expression is altered by (i) the deficiency of uPAR or uPA (urokinase-type plasminogen activator), and (ii) traumatic brain injury (TBI). SRPX2 expression was assessed in wild type (Wt), Plaur-/- (uPAR-deficient), and Plau-/- (uPA-deficient) mice, with and without controlled cortical impact injury (CCI). The number of SRPX2+ neurons in hypothalamus was comparable to that in Wt littermates in Plaur-/- (2985 ±â€¯138 vs. 2890 ±â€¯92, p > 0.05) and Plau-/- mice (2180 ±â€¯232 vs. 2027 ±â€¯77, p > 0.05). The number of hypothalamic SRPX2+ neurons in the Wt-CCI group was comparable to that in controls (3645 ±â€¯288 vs. 3385 ±â€¯192, p > 0.05). Hypothalamic, hippocampal and thalamic Srpx2 gene expression was unaltered after TBI. However, at 4 days post-TBI Srpx2 gene expression was upregulated in the perilesional cortex of Plau-/--CCI mice up to 123% of that in the sham group (p < 0.05). Unsupervised hierarchical clustering using SRPX2 expression did not identify genotype or injury-specific clusters. Our data demonstrate that SRPX2 expression in the hypothalamus is resistant to genetic deficiencies in the urokinase-system or to the hypothalamus-affecting TBI. The contribution of elevated Srpx2 gene expression in perilesional cortex to post-TBI recovery process, however, requires further exploration.

Medicinal plants in traumatic brain injury: Neuroprotective mechanisms revisited.

Traumatic brain injury (TBI) is the most prevalent health problem affecting all age groups, and leads to many secondary problems in other organs especially kidneys, gastrointestinal tract, and heart function. In this review, the search terms were TBI, fluid percussion injury, cold injury, weight drop impact acceleration injury, lateral fluid percussion, cortical impact injury, and blast injury. Studies with Actaea racemosa, Artemisia annua, Aframomum melegueta, Carthamus tinctorius, Cinnamomum zeylanicum, Crocus sativus, Cnidium monnieri, Curcuma longa, Gastrodia elata, Malva sylvestris, Da Chuanxiong Formula, Erigeron breviscapus, Panax ginseng, Salvia tomentosa, Satureja khuzistanica, Nigella sativa, Drynaria fortune, Dracaena cochinchinensis, Polygonum cuspidatum, Rosmarinus officinalis, Rheum tanguticum, Centella asiatica, and Curcuma zedoaria show a significant decrease in neuronal injury by different mechanisms such as increasing superoxide dismutase and catalase activities, suppressing nuclear factor kappa B (NF-κB), interleukin 1 (IL-1), glial fibrillary acidic protein, and IL-6 expression. The aim of this study was to evaluate the neuroprotective effects of medicinal plants in central nervous system pathologies by reviewing the available literature.

Rapid characterization of the absorbed constituents in rat serum after oral administration and action mechanism of Naozhenning granule using LC-MS and network pharmacology.

Naozhenning granule is a Chinese herbal formula, which is mainly used in the treatment of concussion, cerebral post-traumatic syndrome. Although its effectiveness has been certified in the clinical use, the mechanism of action and bioactive components of Naozhenning remain unknown. In this study, the ultrahigh performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry was applied to identify the absorbed constituents of Naozhenning in the rat serum. A total of 60 compounds, including 30 prototype components and 30 metabolites were identified. Then the absorbed constituents were subjected to the network pharmacology analysis. The compound-target-disease (CTD) and KEGG pathway analysis revealed that 40 absorbed constituents, 56 target genes and three key pathways such as RAS, PI3K/Akt, MAPK, TGFß were probably related with the efficacy of Naozhenning against cerebral trauma and cerebral concussion. The results provided a scientific basis for understanding the bioactive compounds and the pharmacological mechanism of Naozhenning granule.

Melatonin receptor activation provides cerebral protection after traumatic brain injury by mitigating oxidative stress and inflammation via the Nrf2 signaling pathway.

Traumatic brain injury (TBI) is a principal cause of death and disability worldwide. Melatonin, a hormone made by the pineal gland, is known to have anti-inflammatory and antioxidant properties. In this study, using a weight-drop model of TBI, we investigated the protective effects of ramelteon, a melatonin MT1/MT2 receptor agonist, and its underlying mechanisms of action. Administration of ramelteon (10 mg/kg) daily at 10:00 a.m. alleviated TBI-induced early brain damage on day 3 and long-term neurobehavioral deficits on day 28 in C57BL/6 mice. Ramelteon also increased the protein levels of interleukin (IL)-10, IL-4, superoxide dismutase (SOD), glutathione, and glutathione peroxidase and reduced the protein levels of IL-1ß, tumor necrosis factor, and malondialdehyde in brain tissue and serum on days 1, 3, and 7 post-TBI. Similarly, ramelteon attenuated microglial and astrocyte activation in the perilesional cortex on day 3. Furthermore, ramelteon decreased Keap 1 expression, promoted nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation, and increased levels of downstream proteins, including SOD-1, heme oxygenase-1, and NQO1 on day 3 post-TBI. However, in Nrf2 knockout mice with TBI, ramelteon did not decrease the lesion volume, neuronal degeneration, or myelin loss on day 3; nor did it mitigate depression-like behavior or most motor behavior deficits on day 28. Thus, timed ramelteon treatment appears to prevent inflammation and oxidative stress via the Nrf2-antioxidant response element pathway and might represent a potential chronotherapeutic strategy for treating TBI.

Effect of acupuncture on the TLR2/4-NF-κB signalling pathway in a rat model of traumatic brain injury.

OBJECTIVE: To study the effect of acupuncture on the TLR2/4-NF-κB signalling pathway in the cortex of Sprague-Dawley rats following traumatic brain injury (TBI), and investigate the possible mechanism underlying the effects of acupuncture on scar repair. METHODS: TBI was established using Feeney's free-falling epidural percussion model. In total, 108 rats were randomly divided into a normal group (n=18), untreated TBI model group (TBI group, n=36) and manual acupuncture-treated TBI group (TBI+MA, n=36). Each group of rats was subdivided into three time groups: 3-day (3d), 7-day (7d) and 14-day (14d). No treatment was given to rats in the normal and TBI groups. The TBI+MA group received manual acupuncture at GV20, GV26, GV16 through GV15, and bilateral LI4. mRNA expression of TLR2, TLR4, NF-κB and protein in the rat cortices was quantified using real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blot analyses. RESULTS: The modified neurological severity score (mNSS) scores of the TBI+MA group were improved compared with baseline scores 12 hours after modelling, and improved at 7d and 14d compared with the TBI group (P<0.05), while the score of the TBI group did not improve until 14d compared to baseline. mRNA and protein expression of TLR2, TLR4 and NF-κB in the TBI group were higher than the normal group at 3d (P<0.05), reached a peak at 7d, then began to decrease at 14d. mRNA and protein expression of TLR2, TLR4 and NF-κB were higher in the TBI+MA group compared with the TBI group at 3d (P<0.05), were significantly down-regulated at 7d (P<0.01), and decreased to normal levels at 14d. CONCLUSIONS: Acupuncture has a bidirectional regulatory effect on the TLR2/4-NF-κB signalling pathway-related genes TLR2, TLR4 and NF-κB in the TBI rat cortex, promoting their expression in the early stage and inhibiting it in the later stage.

Early electroacupuncture treatment ameliorates neuroinflammation in rats with traumatic brain injury.

BACKGROUND: Neuroinflammation is the leading cause of neurological sequelae after traumatic brain injury (TBI). The aim of the present study was to investigate whether the neuroprotective effects of electroacupuncture (EA) are mediated by anti-neuroinflammatory effects in a rat model of TBI. METHODS: Male Sprague-Dawley rats were randomly divided into three groups: sham-operated, TBI control, and EA-treated. The animals in the sham-operated group underwent a sham operation, those in the TBI control group were subjected to TBI, but not EA, and those in the EA group were treated with EA for 60 min immediately after TBI, daily for 3 consecutive days. EA was applied at the acupuncture points GV20, GV26, LI4, and KI1, using a dense-dispersed wave, at frequencies of 0.2 and 1 Hz, and an amplitude of 1 mA. Cell infarction volume (TTC stain), neuronal apoptosis (markers: TUNEL and Caspase-3), activation of microglia (marker: Iba1) and astrocytes (marker: GFAP), and tumor necrosis factor (TNF)-α expression in the microglia and astrocytes were evaluated by immunofluorescence. Functional outcomes were assessed using the inclined plane test. All tests were performed 72 h after TBI. RESULTS: We found that TBI-induced loss of grasp strength, infarction volume, neuronal apoptosis, microglial and astrocyte activation, and TNF-α expression in activated microglia and astrocytes were significantly attenuated by EA treatment. CONCLUSIONS: Treatment of TBI in the acute stage with EA for 60 min daily for 3 days could ameliorate neuroinflammation. This may thus represent a mechanism by which functional recovery can occur after TBI.