OBJECTIVES: To observe the effect of 4-(arylethynyl)-pyrrolo[2,3-d] pyrimidine (10b) on post-traumatic stress disorder (PTSD)-like behaviors and ERK1/2-SGK1 signaling pathway in mice. METHODS: C57BL/6 mouse models exposed to single prolonged stress (SPS) were treated with daily gavage of saline, 10b at low, moderate and high doses, or paroxetine for 14 days. The changes in PTSD-like behaviors of SPS mice with different treatments were observed using behavioral tests. Western blotting and immunofluorescence assay were used to detect the protein expression levels of mGluR5, p-ERK, and SGK1 in the hippocampus of the mice. Pathological changes in the liver and kidney tissues of the mice were examined using HE staining. Molecular docking and molecular dynamics analyses were employed to evaluate the binding stability between the compound 10b and mGluR5. RESULTS: Compared to the normal control mice, the SPS mice exhibited obvious PTSD-like behaviors with increased hippocampal expressions of mGluR5 and p-ERK proteins and decreased SGK1 protein expression. Compound 10b significantly ameliorated behavioral abnormalities in SPS mice, inhibited mGluR5 expression, and reversed the dysregulation of p-ERK and SGK1. No obvious liver or kidney toxicity was observed after 10b treatment. Molecular docking and dynamics studies demonstrated a stable interaction between 10b and mGluR5. CONCLUSIONS The compound 10b ameliorates PTSD-like behaviors induced by SPS in mice possibly by inhibiting mGluR5 expression to modulate the ERK1/2-SGK1 signaling pathway.
Animals ; Stress Disorders, Post-Traumatic/drug therapy* ; Receptor, Metabotropic Glutamate 5/metabolism* ; Mice, Inbred C57BL ; Mice ; Protein Serine-Threonine Kinases/metabolism* ; Pyrimidines/pharmacology* ; Immediate-Early Proteins/metabolism* ; Signal Transduction/drug effects* ; MAP Kinase Signaling System/drug effects* ; Male ; Molecular Docking Simulation ; Hippocampus/metabolism*

OBJECTIVES: To investigate the mechanism underlying the therapeutic effect of electroacupuncture (EA) on post-traumatic stress disorder (PTSD) in rats. METHODS: Forty male SD rats were randomized equally into blank control group, PTSD model group, sham-acupuncture group, paroxetine group, and EA group. In the latter 3 groups, the rat models of PTSD, induced by continuous single-prolonged stress and plantar electrical stimulation, were treated with EA at GV20, GV24, BL18 and BL23 acupoints for 15 min (5 times a week for 3 weeks), sham-acupuncture without electrical stimulation, or gavage with paroxetine suspension on the same schedule. Behavioral changes of the rats were evaluated using open field test (OFT) and elevated plus maze (EPM) test. Hippocampal pathologies and neuronal changes were examined with HE and Nissl staining, and mitochondrial ultrastructure was examined using electron microscopy. The mRNA and protein expression levels of Bcl-2, Bax, and caspase-3 were detected by RT-qPCR and immunofluorescence staining. RESULTS: The rat models of PTSD showed significantly reduced total distance traveled in OFT and distance and time spent in the open arms of the EPM, with decreased hippocampal neurons, obvious neuronal and mitochondrial pathologies, decreased hippocampal expression of Bcl-2, and increased Bax and caspase-3 expressions. Treatments with paroxetine and EA both significantly improved behavioral changes of the rat models, increased the number of Nissl-stained neurons, obviously alleviated pathologies in the hippocampal neurons and mitochondrial ultrastructure, increased hippocampal Bcl-2 expression, and lowered caspase-3 expressions. Paroxetine showed significantly better effect than EA for improving performance of the rats in EPM test, whereas sham-acupuncture did not produce any significant improvement. CONCLUSIONS EA alleviates PTSD in rats possibly by upregulating Bcl-2 and downregulating Bax and caspase-3, thereby ameliorating hippocampal mitochondrial damage.
Animals ; Electroacupuncture ; Stress Disorders, Post-Traumatic/metabolism* ; Hippocampus/pathology* ; Rats, Sprague-Dawley ; Male ; Rats ; Mitochondria/pathology* ; Signal Transduction ; bcl-2-Associated X Protein/metabolism* ; Caspase 3/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Disease Models, Animal

Post-traumatic stress disorder (PTSD) is a psychiatric disorder caused by traumatic past experiences, rooted in the neurocircuits of fear memory formation. Memory processes include encoding, storing, and recalling to forgetting, suggesting the potential to erase fear memories through timely interventions. Conventional strategies such as medications or electroconvulsive therapy often fail to provide permanent relief and come with significant side-effects. This review explores how fear memory may be erased, particularly focusing on the mnemonic phases of reconsolidation and extinction. Reconsolidation strengthens memory, while extinction weakens it. Interfering with memory reconsolidation could diminish the fear response. Alternatively, the extinction of acquired memory could reduce the fear memory response. This review summarizes experimental animal models of PTSD, examines the nature and epidemiology of reconsolidation to extinction, and discusses current behavioral therapy aimed at transforming fear memories to treat PTSD. In sum, understanding how fear memory updates holds significant promise for PTSD treatment.
Fear/psychology* ; Extinction, Psychological/physiology* ; Animals ; Stress Disorders, Post-Traumatic/psychology* ; Humans ; Memory Consolidation/physiology* ; Memory/physiology*

OBJECTIVE: To identify early potential risk factors for hospital-acquired pneumonia (HAP) in patients with mild traumatic brain injury (mTBI), construct a risk prediction model, and evaluate its predictive efficacy. METHODS: A case-control study was conducted using clinical data from mTBI patients admitted to the neurosurgery department of Changzhou Second People's Hospital from September 2021 to September 2023. The patients were divided into two groups based on whether they developed HAP. Clinical data within 48 hours of admission were statistically analyzed to identify factors influencing HAP occurrence through univariate analysis. Least absolute shrinkage and selection operator (LASSO) regression analysis was employed for feature selection to identify the most influential variables. The dataset was divided into training and validation sets in a 7:3 ratio. A multivariate Logistic regression analysis was then performed using the training set to construct the prediction model, exploring the risk factors for HAP in mTBI patients and conducting internal validation in the validation set. Receiver operator characteristic curve (ROC curve), decision curve analysis (DCA), and calibration curve were utilized to assess the sensitivity, specificity, decision value, and predictive accuracy of the prediction model. RESULTS: A total of 677 mTBI patients were included, with 257 in the HAP group and 420 in the non-HAP group. The significant differences were found between the two groups in terms of age, maximum body temperature (MaxT), maximum heart rate (MaxHR), maximum systolic blood pressure (MaxSBP), minimum systolic blood pressure (MinSBP), maximum respiratory rate (MaxRR), cause of injury, and laboratory indicators [C-reactive protein (CRP), procalcitonin (PCT), neutrophil count (NEUT), erythrocyte sedimentation rate (ESR), fibrinogen (FBG), fibrinogen equivalent units (FEU), prothrombin time (PT), activated partial thromboplastin time (APTT), total cholesterol (TC), lactate dehydrogenase (LDH), prealbumin (PAB), albumin (Alb), blood urea nitrogen (BUN), serum creatinine (SCr), hematocrit (HCT), hemoglobin (Hb), platelet count (PLT), glucose (Glu), K⁺, Na⁺], suggesting they could be potential risk factors for HAP in mTBI patients. After LASSO regression analysis, the key risk factors were enrolled in the multivariate Logistic regression analysis. The results revealed that the cause of injury being a traffic accident [odds ratio (OR) = 2.199, 95% confidence interval (95%CI) was 1.124-4.398, P = 0.023], NEUT (OR = 1.330, 95%CI was 1.214-1.469, P < 0.001), ESR (OR = 1.053, 95%CI was 1.019-1.090, P = 0.003), FBG (OR = 0.272, 95%CI was 0.158-0.445, P < 0.001), PT (OR = 0.253, 95%CI was 0.144-0.422, P < 0.001), APTT (OR = 0.689, 95%CI was 0.578-0.811, P < 0.001), Alb (OR = 0.734, 95%CI was 0.654-0.815, P < 0.001), BUN (OR = 0.720, 95%CI was 0.547-0.934, P = 0.016), and Na⁺ (OR = 0.756, 95%CI was 0.670-0.843, P < 0.001) could serve as main risk factors for constructing the prediction model. Calibration curves demonstrated good calibration of the prediction model in both training and validation sets with no evident over fitting. ROC curve analysis showed that the area under the ROC curve (AUC) of the prediction model in the training set was 0.943 (95%CI was 0.921-0.965, P < 0.001), with a sensitivity of 83.6% and a specificity of 91.5%. In the validation set, the AUC was 0.917 (95%CI was 0.878-0.957, P < 0.001), with a sensitivity of 90.1% and a specificity of 85.0%. DCA indicated that the prediction model had a high net benefit, suggesting practical clinical applicability. CONCLUSIONS The cause of injury being a traffic accident, NEUT, ESR, FBG, PT, APTT, Alb, BUN, and Na⁺ are identified as major risk factors influencing the occurrence of HAP in mTBI patients. The prediction model constructed using these parameters effectively assesses the likelihood of HAP in mTBI patients.
Humans ; Risk Factors ; Case-Control Studies ; Logistic Models ; Healthcare-Associated Pneumonia/epidemiology* ; Brain Injuries, Traumatic/complications* ; Male ; Female ; ROC Curve ; Pneumonia/etiology* ; Middle Aged ; Adult

OBJECTIVE: To investigate the frequency and related factors of ineffective triggering (IT) and double triggering (DT) in patients with acute brain injury undergoing invasive mechanical ventilation. METHODS: A retrospective cohort study was conducted using data from a single-center observational trial. Patients with acute brain injury [traumatic brain injury, stroke, and post-craniotomy for brain tumors] undergoing mechanical ventilation in the intensive care unit (ICU) of Beijing Tiantan Hospital, Capital Medical University between June 2017 and July 2019 were retrospectively analyzed. Demographic and clinical data were collected. Respiratory parameters and waveforms during the first 3 days of mechanical ventilation were recorded, with 15-minute waveform segments collected 4 times daily. Airway occlusion pressure (P_0.1) was measured via end-expiratory hold at the end of each recording. IT and DT were identified based on airway pressure, flow, and esophageal pressure waveforms, and the ineffective triggering index (ITI) and DT incidence were calculated. Multivariate Logistic regression was used to identify factors associated with IT and DT. RESULTS: A total of 94 patients with acute brain injury were ultimately enrolled, including 19 cases of traumatic brain injury (20.2%), 39 cases of stroke (41.5%), and 36 cases of post-craniotomy for brain tumor (38.3%). Supratentorial injury was observed in 49 patients (52.1%), while infratentorial injury was identified in 45 patients (47.9%). A total of 94 patients with 1 018 datasets were analyzed; 684 (67.2%) datasets were on pressure support ventilation (PSV), and 334 (32.8%) were on mandatory ventilation. IT was detected in 810 (79.6%) datasets, with a median incidence of 2.1% (0.3%, 12.0%). Datasets demonstrating IT were characterized by lower P_0.1, higher tidal volume (VT), reduced respiratory rate (RR), and decreased minute ventilation (MV) compared to those without IT. The proportion of datasets exhibiting IT was higher during PSV than in mandatory ventilation [83.8% (573/684) vs. 71.0% (237/334), P < 0.05], while, the prevalence of ITI ≥ 10% was lower [23.8% (163/684) vs. 33.5% (112/334), P < 0.05]. DT was detected in 305 datasets (30%), with a median incidence of 0.6% (0.4%, 1.3%). Datasets exhibiting DT were characterized by higher VT, reduced RR, and lower pressure support levels. The incidence of DT was lower in PSV compared to mandatory ventilation modes [0% (0%, 0.3%) vs. 0% (0%, 0.5%), P < 0.05]. The post-craniotomy for brain tumors group exhibited higher ITI, lower RR, reduced MV, and a greater proportion of infratentorial lesions, compared to the TBI group. The infratentorial lesion group demonstrated higher ITI and incidence of DT compared to the supratentorial lesion group [ITI: 3.1% (0.7%, 17.8%) vs. 1.5% (0%, 8.3%), incidence of DT: 0% (0%, 0.5%) vs. 0% (0%, 0%), both P < 0.05]. After adjusting for confounding factors through multivariate logistic regression analysis, infratentorial lesion [odds ratio (OR) = 2.029, 95% confidence interval (95%CI) was 1.465-2.811, P < 0.001], lower P_0.1 (OR = 0.714, 95%CI was 0.616-0.827, P < 0.001), and mandatory ventilation (OR = 1.613, 95%CI was 1.164-2.236, P = 0.004) were independently associated with IT. Additionally, infratentorial lesion (OR = 1.618, 95%CI was 1.213-2.157, P = 0.001), large tidal volume (OR = 1.222, 95%CI was 1.137-1.314, P < 0.001), lower pressure support levels (OR = 0.876, 95%CI was 0.829-0.925, P < 0.001), and mandatory ventilation (OR = 2.750, 95%CI was 1.983-3.814, P < 0.001) were independently associated with DT. CONCLUSION IT and DT were common in patients with acute brain injury. Infratentorial lesions and mandatory ventilation were independently associated with both IT and DT.
Humans ; Respiration, Artificial/methods* ; Retrospective Studies ; Brain Injuries/therapy* ; Intensive Care Units ; Male ; Female ; Middle Aged ; Brain Injuries, Traumatic/therapy* ; Logistic Models ; Aged ; Adult

Traumatic brain injury (TBI), as a significant central nervous system damage disease with high frequency in the world, leads to a huge number of patients with impaired health and lower quality of life every year. Lung injury is a common and dangerous consequence, which dramatically raises the mortality of patients. Discovering the pathophysiology of lung injury after TBI and discovering viable therapeutic targets has become an important need for clinical diagnosis and therapy. Neurotransmitters, as the fundamental chemical agents of the nervous system for signal transmission, not only govern neuronal activity and apoptosis in TBI but also significantly influence the pathophysiological mechanisms of lung injury subsequent to TBI. The imbalance is intricately linked to the onset and progression of lung damage. This paper systematically reviews the clinical characteristics and predominant pathogenesis of lung injury following TBI, emphasizing the role of key neurotransmitters, including glutamate (Glu), γ-aminobutyric acid (GABA), norepinephrine (NE), dopamine (DA), and acetylcholine (ACh), in lung injury post-TBI. It examines their influence on inflammatory response, vascular permeability, and pulmonary circulation function. Additionally, the paper evaluates the research advancements and potential applications of targeted therapeutic strategies for various neurotransmitter systems, such as receptor antagonists, transporter inhibitors, and neurotransmitter analogues. This research aims to offer a theoretical framework for clarifying the neural regulatory mechanisms of lung injury following TBI and to establish a basis for the development of novel therapeutic strategies and enhancement of the prognosis of the patients.
Humans ; Brain Injuries, Traumatic/metabolism* ; Neurotransmitter Agents/metabolism* ; Lung Injury/metabolism* ; gamma-Aminobutyric Acid/metabolism* ; Glutamic Acid/metabolism* ; Norepinephrine/metabolism* ; Dopamine/metabolism* ; Acetylcholine/metabolism*

OBJECTIVE: To elucidate the specific mechanisms by which electroacupuncture (EA) alleviates anxiety and fear behaviors associated with posttraumatic stress disorder (PTSD), focusing on the role of lipocalin-2 (Lcn2). METHODS: The PTSD mouse model was subjected to single prolonged stress and shock (SPS&S), and the animals received 15 min sessions of EA at Shenmen acupoint (HT7). Behavioral tests were used to investigate the effects of EA at HT7 on anxiety and fear. Western blotting and enzyme-linked immunosorbent assay were used to quantify Lcn2 and inflammatory cytokine levels in the prefrontal cortex (PFC). Additionally, the activity of PFC neurons was evaluated by immunofluorescence and in vivo electrophysiology. RESULTS: Mice subjected to SPS&S presented increased anxiety- and fear-like behaviors. Lcn2 expression in the PFC was significantly upregulated following SPS&S, leading to increased expression of the proinflammatory cytokines tumor necrosis factor-α and interleukin-6 and suppression of PFC neuronal activity. However, EA at HT7 inhibited Lcn2 release, reducing neuroinflammation and hypoexcitability in the PFC. Lcn2 overexpression mitigated the effects of EA at HT7, resulting in anxiety- and fear-like behaviors. CONCLUSION EA at HT7 can ameliorate PTSD-associated anxiety and fear, and its mechanism of action appears to involve the inhibition of Lcn2-mediated neural activity and inflammation in the PFC. Please cite this article as: Yang YD, Zhong W, Chen M, Tang QC, Li Y, Yao LL, et al. Electroacupuncture alleviates behaviors associated with posttraumatic stress disorder by modulating lipocalin-2-mediated neuroinflammation and neuronal activity in the prefrontal cortex. J Integr Med. 2025; 23(5):537-547.
Electroacupuncture ; Stress Disorders, Post-Traumatic/metabolism* ; Animals ; Lipocalin-2/metabolism* ; Prefrontal Cortex/physiopathology* ; Male ; Mice ; Neurons/physiology* ; Disease Models, Animal ; Fear ; Behavior, Animal ; Mice, Inbred C57BL ; Neuroinflammatory Diseases/metabolism* ; Anxiety/therapy* ; Acupuncture Points

This study integrates metabolomics and transcriptomics to explore the immediate effects of Angong Niuhuang Pills(ANP) in intervening traumatic brain injury(TBI) in rats. A TBI model was successfully established in rats using the optimized Feeney free-fall impact technique. Rats were randomly divided into sham operation(sham) group, model(Mod) group, positive drug(piracetam) group, ANP low-dose(ANP-L) group, and ANP high-dose(ANP-H) group according to a random number table. Nissl staining and immunofluorescence were used to count the number of Nissl bodies and detect B-cell lymphoma-2(Bcl-2) gene, caspase-3, and tumor protein 53(TP53) expression in brain tissue, and enzyme-linked immunosorbent assay(ELISA) was used to measure prostaglandin-endoperoxide synthase 2(PTGS2) level in rat brain tissue. Metabolomics and transcriptomics analyses were conducted for brain tissue from sham, Mod, and ANP-H groups. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were carried out to indicate the mechanisms of ANP in the intervention of TBI. Integrative metabolomics and transcriptomics analysis revealed the metabolic pathways involved in ANP's intervention in TBI. The results showed that ANP significantly increased the number of Nissl bodies in TBI rat brain tissue, upregulated Bcl-2 expression, and downregulated the levels of caspase-3, TP53, and PTGS2. Compared to the Mod group, the ANP-H group significantly upregulated 12 differential metabolites(DMs) and downregulated 25 DMs. Five key metabolic pathways were identified, including glycerophospholipid metabolism, pyrimidine metabolism, glycine, threonine, and serine metabolism, arginine and proline metabolism, and D-amino acid metabolism. Transcriptomics identified 730 upregulated and 612 downregulated differentially expressed genes(DEGs). Enrichment analysis highlighted that biological functions related to inflammatory responses and apoptotic processes, and key signaling pathways, including phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt) and mitogen-activated protein kinase(MAPK) were significantly enriched. The data of transcriptomics and metabolomics pinpointed three key metabolic pathways, i.e., glycerophospholipid metabolism, pyrimidine metabolism, and glycine, threonine, and serine metabolism.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Brain Injuries, Traumatic/metabolism* ; Male ; Metabolomics ; Rats, Sprague-Dawley ; Transcriptome/drug effects* ; Cyclooxygenase 2/genetics* ; Brain/metabolism* ; Caspase 3/genetics* ; Humans ; Tumor Suppressor Protein p53/genetics*

OBJECTIVE: To explore the current status and changing trends of the disease burden of traumatic brain injury (TBI) in China from 1990 to 2023, and to quantitatively assess the impact of different influencing factors on this disease burden, thereby providing references for the prevention of TBI. METHODS: Based on the 2023 Global Burden of Disease Study (GBD), indicators including incidence and years lived with disability (YLDs) were used to analyze the status and changing trends of TBI disease burden in China from 1990 to 2023. Additionally, the decomposition method established by Gupta was adopted to quantify the effects of population growth, population aging, age-specific incidence rate, and disease severity on YLDs. RESULTS: From 1990 to 2023, the age-standardized incidence rate and YLDs rate of TBI in China showed an overall upward trend, with a significant downward trend between 2015 and 2020, followed by a resumption of upward trend after 2020. The disease burden of TBI in males was higher than that in females, with a larger increase amplitude. The elderly population had higher TBI incidence rate and YLDs rate, also with a larger upward amplitude. Falls were the main cause of TBI in China, and the changing trend of the disease burden caused by falls was consistent with the overall trend of TBI disease burden; meanwhile, the elderly population bore a relatively high disease burden from falls. Taking 1990 as the baseline, the growth rates of YLDs in males and females in 2023 were 101.54% and 101.40%, respectively. For males, the proportions of YLDs growth attributed to population growth, population aging, age-specific incidence rate, and disease severity were 26.91%, 49.62%, 37.74%, and -12.73%, respectively; for females, the corresponding proportions were 28.85%, 57.69%, 27.65%, and -12.79%. CONCLUSION From 1990 to 2023, population aging had a significant impact on the disease burden of TBI in China. Strengthening the prevention and control of falls and paying close attention to males and the elderly population should be the key focuses of TBI prevention and control work in China in the future.
Humans ; Brain Injuries, Traumatic/epidemiology* ; China/epidemiology* ; Male ; Female ; Incidence ; Middle Aged ; Aged ; Adult ; Cost of Illness ; Adolescent ; Young Adult ; Persons with Disabilities/statistics & numerical data* ; Child ; Global Burden of Disease ; Disability-Adjusted Life Years ; Child, Preschool ; Infant ; Aged, 80 and over

Objective To investigate the effects and molecular mechanism of Homer protein homolog 1a (Homer 1a) overexpression on nerve injury in mice with traumatic brain injury (TBI). Methods Sixty male C57BL/6 mice were randomly divided into five groups: sham group, TBI group, empty lentivirus (Lv-NC) group, Homer 1a overexpression lentivirus (Lv-Homer 1a) group and Lv-Homer 1a + 740 Y-P group, with 12 mice in each group. The lentivirus was orthotopic injected into the cerebral cortex of mice 5 d before modeling, while 740 Y-P was injected intraperitoneally 1 d before modeling. The TBI model was established using the free-fall impact method, and the modified neurological severity scores (mNSS) of the mice was assessed 72 h post-surgery. The water content of brain tissue was quantified, and the histopathological damage and neuronal loss in brain tissue were assessed using HE staining and Nissl staining respectively. The formation of autophagosomes in brain tissue was observed by transmission electron microscopy. The protein expression levels of Homer 1a, microtubule-associated protein 1 light chain 3B (LC3B), Beclin 1, phosphatidylinositol 3-kinase (PI3K), phosphorylation PI3K(p-PI3K), protein kinase B (AKT), p-AKT, mammalian target of rapamycin (mTOR), and p-mTOR in brain tissue were detected by Western blot analysis. Results Compared to the sham group, the mice in the TBI group exhibited a significant increase in mNSS and cerebral water content. Moreover, severe brain tissue pathological damage was observed, accompanied by a substantial loss of neurons and an increase in autophagosome formation. The protein expressions of Homer 1a and Beclin 1, as well as the protein ratio of LC3B-II/LC3B-I, in brain tissues were significantly elevated, while the protein ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR were significantly reduced. Compared to the TBI group, the Lv-Homer 1a group exhibited reduced mNSS and brain water content. Additionally, there was an improvement in pathological brain tissue damage and neuron loss. Furthermore, there was an increase in autophagosome formation and expression of autophagy-related proteins, while the protein ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR were decreased. Compared to the Lv-Homer 1a group, the nerve injury in the Lv-Homer 1a+740 Y-P group was exacerbated, accompanied by a reduction in autophagosome formation and expression of autophagy-related proteins, while the PI3K/AKT/mTOR signaling pathway was activated. Conclusion Overexpression of Homer 1a effectively mitigates neurological damage in TBI mice, potentially through modulation of autophagy mediated by the PI3K/AKT/mTOR signaling pathway.
Animals ; TOR Serine-Threonine Kinases/genetics* ; Autophagy ; Brain Injuries, Traumatic/pathology* ; Male ; Proto-Oncogene Proteins c-akt/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Homer Scaffolding Proteins/metabolism* ; Mice, Inbred C57BL ; Signal Transduction ; Mice