Dexmedetomidine-mediated protection against septic liver injury depends on TLR4/MyD88/NF-κB signaling downregulation partly via cholinergic anti-inflammatory mechanisms.

BACKGROUND: Uncontrolled inflammatory responses exacerbate the pathogenesis of septic acute liver injury (ALI), posing a lethal threat to the host. Dexmedetomidine (DEX) has been reported to possess protective properties in inflammatory conditions. This study aimed to investigate whether DEX pretreatment exhibits hepatoprotection against ALI induced by lipopolysaccharide (LPS) in rats and determine its possible molecular mechanism. METHODS: Septic ALI was induced by intravenous injection of LPS. The rats received DEX intraperitoneally 30 min before LPS administration. α-Bungarotoxin (α-BGT), a specific α7 nicotinic acetylcholine receptor (α7nAChR) antagonist, was administered intraperitoneally 1 h before LPS exposure. The role of the vagus nerve was verified by performing unilateral cervical vagotomy or sham surgery before sepsis. RESULTS: The expression of α7nAChR, toll-like receptor 4 (TLR4), high mobility group box 1 (HMGB1), and cleaved caspase-3 increased, peaking 24 h during sepsis. DEX enhanced α7nAChR activation and reduced TLR4 expression upon challenge with LPS. DEX significantly prevented LPS-induced ALI, which was associated with increased survival, the mitigation of pathological changes, the attenuation of inflammatory cytokine expression and apoptosis, and the downregulation of TLR4/MyD88/NF-κB pathway. Moreover, the hepatoprotective effect of DEX was abolished by α-BGT. Further investigation established that vagotomy, compared to sham surgery, triggered more severe pathogenic manifestations and higher proinflammatory cytokine levels. The inhibitory effects of DEX were shown in sham-operated rats but not in vagotomized rats. CONCLUSIONS: Our data highlight the pivotal function of α7nAChR and intact vagus nerves in protecting against LPS-induced ALI through inhibiting the TLR4/MyD88/NF-κB signaling pathway upon pretreatment with DEX.

[The value of diffusion tensor imaging and fiber tractography in cervical spondylotic myelopathy].

OBJECTIVE: To study the diagnostic value of diffusion tensor imaging (DTI) in cervical spondylotic myelopathy. METHODS: Twenty healthy volunteers and fifty patients with cervical spondylotic myelopathy underwent DTI in the Affiliated Hospital of Medical College of Ningbo University from January 2014 to April 2015. Healthy volunteers served as controls. Fifty patients were divided into three groups (group A , B, C) according to cervical MRI scan standard. Group A (17 cases) had only the dura mater spinalis compressed; Group B (23 cases) showed the cervical spinal cord compressed, but no high signal in it; Group C (10 cases) had the cervical spinal cord compressed with high signal in the same level. The average apparent diffusion coefficients(ADC) and fractional anisotropy (FA)values in these examinee were analyzed and all subjects were performed fiber tracking. RESULTS: There was no statistically significant differences in ADC and FA values in C2/C3, C3/C4, C4/C5, C5/C6, C6/C7 of control group (P>0.05). The average ADC and FA values in control group were (0.875 +/- 0.096) x10(3) mm2/s and 0.720 +/- 0.051, respectively; compared with group A,there was no statistically significant difference; compared with group B and C, there was significant difference; comparison among group A, B, C, there was significant differences. CONCLUSION: DTI can early and accurately quantify the changes of microstructure in cervical spondylotic myelopathy. Fiber tracking can show the damage range of spinal cord lesions.

[Diagnostic value of 3D-indirect magnetic resonance arthrography in detecting meniscal tears of the knees].

OBJECTIVE: To explore the diagnostic value of 3D-indirectmagnetic resonance (MR) arthrography in detecting meniscustears of the knees. METHODS: Form January 2013 to January 2014, routine plain MR of the knees followed by the 3D-indirect MR arthrography was performed in 42 patients with suspected meniscal tears clinically. There were 31 males and 11 females, with an average age of 38.4 years old (ranged, 21 to 67 years old). The duration of the course ranged from 2 h to 15 d. The clinical symptom was knee pain. All the patients got subsequently arthroscopic examination or operation. The sensitivity and specificity of routine plain MR and 3D-indirect MR arthrography were compared based on the results of arthroscopic examination or operation. RESULTS: The signal intensity in the area of meniscal tears on image of 3D-indirect MR arthrography was obviously higher than that of routine plain MR. The sensitivity of 3D-indirect MR arthrography was 85.79% (87/102), while the routine plain MR was 52.94% (54/102), and the specificity improved from 67.78%(61/90) to 86.67%(78/90). The difference was statistically significant (χ2 = 25.90, P < 0.01; χ2 = 9.13, P < 0.01). CONCLUSION: In comparison with the routine plain MR findings, 3D-indirect MR arthrography demonstrates meniscus tears of the knee with the better sensitivity and specificity.