The role and mechanism of TLR4-siRNA in the impairment of learning and memory in young mice induced by isoflurane.

BACKGROUND: Isoflurane can significantly induce inflammation in children without surgical stress. The toll-like receptor 4 (TLR4) is closely related to noninfectious inflammation in the brain. OBJECTIVES: To investigate the role of TLR4-small interfering RNA (siRNA) in learning and memory impairment in young mice induced by isoflurane. MATERIAL AND METHODS: The C57 newborn mice were randomly allocated into normal control (control), isoflurane anesthesia (isoflurane), TLR4 interference empty vector+isoflurane anesthesia (siRNA-NC), and TLR4 interference+isoflurane anesthesia (TLR-siRNA) groups. Their behavior and pathological condition were detected using Morris water maze and hematoxylin and eosin (H&E) staining, respectively. The TLR4, brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate response element-binding protein 1 (CREB1) mRNA expressions were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Serum tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 were detected by means of the enzyme-linked immunosorbent assay (ELISA). Apoptosis rate was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). The TLR4, TNF-α, IL-6, BDNF, CREB1, extracellular signal-regulated kinase 1/2 (ERK1/2), and c-Jun N-terminal kinase (JNK) protein expressions were detected using western blot (WB). RESULTS: Compared with the control group, the number of times the mice crossed the platform, and the time spent at the circumjacent area I and II of the platform were significantly decreased in the isoflurane group; the TLR4, TNF-α and IL-6 expressions were significantly increased in the isoflurane group, as compared to control; the results were reversed after the TLR4 interference. The hippocampal neurons in the isoflurane and siRNA-NC groups showed arrangement disorder and a high number of inflammatory infiltrates, while in the TLR-siRNA group they were closely and orderly arranged. Compared with the control group, the apoptosis rate and JNK protein expression in the isoflurane group were significantly increased, CREB1 protein expression was significantly decreased, and BDNF and ERK1/2 protein expressions showed no significant changes. Compared with the isoflurane group, the apoptosis rate of the TLR-siRNA group was significantly decreased, BDNF and CREB1 protein expressions were significantly increased, and ERK1/2 and JNK did not change significantly. CONCLUSIONS: Isoflurane stimulates the overexpression of inflammatory response factors, playing an important role in the cognitive impairment process. As a mediator of the innate immune inflammatory response, TLR4 plays an important role in the process of cell injury, which may be delayed by blocking the TLR4 signal.

Inhibiting the Piezo1 channel protects microglia from acute hyperglycaemia damage through the JNK1 and mTOR signalling pathways.

AIM: Diabetes is a high-risk factor for neurocognitive dysfunction. Diabetic acute hyperglycaemia accompanied by high osmotic pressure can induce immune cell dysfunction, but its mechanism of action in brain microglia remains unclear. This study aimed to evaluate the role of the mechanically sensitive ion channel Piezo1 in the dysfunction of microglia in acute hyperglycaemia. MATERIALS AND METHODS: To construct an in vitro acute hyperglycaemia model using the BV2 microglial cell line, Piezo1 in microglia was inhibited by GsMTx4 and siRNA, and the changes in microglial function were further evaluated. KEY FINDINGS: High concentrations of glucose upregulated the expression of Piezo1, led to weakened cell proliferation and migration, and reduced the immune response to inflammatory stimulating factors (Aß and LPS). Additionally, LPS upregulated Piezo1 in BV2 microglial cultures in vitro. The activation of Piezo1 channels increased the intracellular Ca2+ concentration and reduced the phosphorylation of JNK1 and mTOR. Inhibiting Piezo1 did not affect cell viability at average glucose concentrations but improved acute HCG-induced cell damage and increased the phosphorylation of JNK1 and mTOR, suggesting that the latter modification may be a potential downstream mechanism of Piezo1. SIGNIFICANCE: Piezo1 is necessary for microglial damage in acute hyperglycaemia and may become a promising target to treat hyperglycaemic brain injury.

Ultrasound-Guided Transversus Abdominis Plane Block for Cesarean Delivery: Injection Site Pain as a New Complication and Dexamethasone Reduced Incidence.

BACKGROUND: Although ultrasound-guided transversus abdominis plane block (TAPB) is widely used in multimodal analgesia after cesarean delivery (CD), the complications of TAPB during analgesia after CD have rarely been reported. METHODS: A total of 84 cases of CD were randomly assigned to either a ropivacaine group (R group) or ropivacaine + dexamethasone group (RD group) in this double-blind trial. The pain site and pain degree at rest and during activity at 2 h, 6 h, 10 h, 12 h, 14 h, 16 h, 20 h, and 24 h after maternal surgery were recorded. The consumption of opioids at 24h, postoperative nausea, vomiting, exhaustion, and other adverse reactions were recorded. RESULTS: A total of 80 patients were included in the analysis of results. A total of 19 patients developed ISP, 14 in the R group and 5 in the RD group. The incidence of ISP in the R and RD groups was 35% and 12.5%, respectively. The results described above showed that combining dexamethasone with ropivacaine reduced the incidence of ISP, and the difference was statistically significant (P<0.05). Two groups of women with positive ISP had higher values of opioid consumption than women with negative ISP, but the difference was not significant. CONCLUSION: Dexamethasone as an adjuvant for ropivacaine can effectively relieve the ISP of ultrasound-guided TAPB after CD, and can enhance the analgesic effect of ropivacaine.

The effect of hypercapnic acidosis preconditioning on rabbit myocardium.

This study observed the protective effect of hypercapnic acidosis preconditioning on rabbit heart suffered from ischemia-reperfusion injury. Hypercapnic acidosis was established in animals with mechanical hypoventilation before ischemia-reperfusion. Thirty-two rabbits were randomly divided into 4 groups, with each having 8 animals in term of the degree of acidification: hypercapnic acidosis group A (group A), hypercapnic acidosis group B (group B), hypercapnic acidosis group C (group C), ischemia and reperfusion group (group IR). Animals in group IR were ventilated normally (tidal volume: 15 mL/kg, breathing rate 35 bpm). The PETCO(2) was maintained at the level of 40-50 mmHg for 30 min. Animals in groups A, B, C received low-frequency, low-volume ventilation to achieve hypercarbonic acidosis and the target levels of PETCO(2) were 75-85,65-75, 55-65 mmHg, respectively, with levels being maintained for 5 min. The animals then were ventilated normally to lower PETCO(2) to 40-50 mmHg. The left anterior branch artery of all the animals was ligated for 30 min and reperfused for 180 min. Then the infarct size was calculated. The cardiomyocytes were morphologically observed and ECG and hemodynamics were monitored on continuous basis. Acid-base balance was measured during procedure. Our results showed that the infarct size was (48.5+/-11.5)% of the risk area in the control group and (42.4+/-7.9)% in group C (P>0.05). Mean infarct size was significantly smaller in group B (34.5%+/-9.4%) (P<0.05 vs control group) and group A (31.0%+/-9.1%) (P<0.01 vs control group). It is concluded that HA-preconditioning can effectively protect the myocardium.

[Effects of ulinastatin on cerebral inflammatory response during cardiopulmonary bypass].

OBJECTIVE: To investigate the effects of ulinastatin (UTI) on cerebral inflammatory response during cardiopulmonary bypass (CPB). METHODS: Twenty-four NYHA II-III patients (13 males and 11 females) aged 23-45 years, undergoing elective cardiac valve replacement under hypothermic CPB were randomly divided into 2 groups: ulinastatin group (Group U, n=12) and control group (Group C, n=12). In group U, UTI (1.2 x 10(4) U/kg) was given intravenously after the induction of anesthesia, 0.6 x 10(4) U/kg UTI was added to the priming solution, and 0.6 x 10(4) U/kg UTI was given about 5 min before the aortic decamping. In Group C, normal saline was given instead of UTI. Internal jugular vein was cannulated and the catheter was advanced retrogradely till jugular bulb. Blood samples were taken simultaneously from artery and jugular bulb after induction of anesthesia (T1), 60 min (T2) and 6 h (T3) after discontinuation of CPB for determination of TNFalpha, IL-6, IL-8 and IL-10. The juguloarterial gradients of these cytokines (deltaTNFalpha, deltaIL-6, deltaIL-8, and deltaIL-10) were calculated. RESULTS: In Group C, arterial levels of TNFalpha, IL-6, IL-8, IL-10 at T2 and T3, deltaTNFalpha, deltaIL-8 and deltaIL-10 at T2, deltaTNFalpha, deltaIL-6 and deltaIL-10 at T3 significantly increased (P < 0.01). deltaIL-8 increased at T3 (P < 0.05). In Group U, arterial levels of IL-6, IL-8, IL-10 at T2, arterial levels of IL-6, IL-8,IL-L-10 and deltaTNFalpha, deltaIL-8 at T3 significantly increased (P < 0.01). Arterial levels of TNFalpha at T2 and T3, deltaTNFalpha, deltaIL-10 at T2, deltaIL-6 at T3 increased (P < 0.05). Arterial levels of TNFalpha, IL-6 and deltaTNFalpha, deltaIL-8 at T2, arterial levels of TNFalpha and deltaIL-6 at T3 in Group U were lower than those in Group C (P < 0.05). Arterial levels of IL-6 at T3, IL-8 at T2 and T3 in Group U were significantly lower than those in Group C (P < 0.01). Arterial levels of IL-10 and deltaIL-10 at T3 in Group U were higher than those in Group C (P < 0.05). CONCLUSION: Systemic and cerebral activation of inflammatory response during CPB can be alleviated by ulinastatin.

[Effect of ulinastatin on human blood coagulation and platelet aggregation in orthopaedic surgery].

OBJECTIVE: To investigate the effect of ulinastatin (UTI) on human blood coagulation and platelet aggregation in orthopaedic surgery. METHODS: Thirty ASA I-II patients without blood dyscrasia and blood coagulation obstacle were randomly divided into two groups: Group I (UTI group, n=15) in which patients received UTI 5000 U/kg, and Group II (control group, n=15) in which patients received NS 100 ml. PT, TT, APTT, IB, INR and PAG1, PAG5, and PAGM were measured at 3 points: pre-infusion (T0), 1 hour after the infusion (T1), and 2 hours after the infusion (T2). RESULTS: Compared with the saline group, APTT and PT of UTI group were prolonged significantly than the baseline (before infusion). In Group I, after the infusion, APT, TT and PT were prolonged significantly than before the infusion. CONCLUSION: UTI 5000 U/kg can ameliorate orthopaedic patients and blood coagulation status,which may reduce microthrombus syndrome in the operation and prevent venous thrombosis after the operation.