Triggering Receptor Expressed on Myeloid Cell-2 Protects PC12 Cells Injury by Inhibiting BV2 Microglial Activation.

Microglia play a crucial role in the activation of immune defense mechanism as the resident macrophages in the central nervous system (CNS). Microglia can eliminate damaged neurons, plaques, and other infectious agents. Triggering receptor expressed on myeloid cell-2 (TREM-2) speculates to be beneficial in preventing inflammation-induced bystander damage of neurons. However, the precise molecular mechanisms underlying the regulation of TREM-2 on neurons are not clarified. We cultured PC12 cells with conditioned medium which was the supernatant of LPS-treated BV2 cells and six groups of PC12 cells (control group, LPS group, TREM-2 WT + LPS group, TREM-2 over-expression + LPS group, siRNA control + LPS group, and siRNA TREM-2 + LPS group) were investigated. The mRNA levels of inflammatory mediators: Nitric oxide synthase (iNOS) and Arginase-1(Arg-1) were quantified by using RT-PCR. Assessment of apoptosis in PC12 cells mediated by BV2 microglia was analyzed using TUNEL assays. The result showed that LPS stimulation significantly enhanced inducible iNOS (M1) production in BV2 cells (P < 0.01), and increased PC12 cells apoptosis (P < 0.01), while reduced the production of Arg-1 (M2) in BV2 cells (P < 0.01). These effects were attenuated by TREM-2 over-expression, but enhanced by TREM-2 silencing. It indicated that TREM-2 inhibited LPS-mediated neuronal apoptosis by down-regulating iNOS and up-regulating the expression of Arg-1 in BV2 microglia. Therefore, our findings may provide new insights in the regulation of TREM-2 on neuronal apoptosis via BV2 microglial M1/M2 modulation.

Anesthesia and postoperative analgesia during unilateral lower-extremity fracture surgeries using multiple injections through catheters beside the lumbar plexus or sciatic nerve.

OBJECTIVE: To compare the clinical effects of anesthesia and postoperative analgesia for patients with unilateral lower-extremity fracture between multiple injections through catheters beside the lumbar plexus or sciatic nerve and continuous epidural analgesia. METHODS: Seventy patients with unilateral lower-extremity fracture scheduled for internal fixation were randomly divided into group N (n = 35) and group E (n = 35). Patients in group N received combined lumbar plexus and sciatic nerve block, then a catheter was inserted into the psoas compartment or beside the sciatic nerve, according to the surgical site, and 25 mL 0.375% ropivacaine was injected into patients in group N through the peripheral nerve catheter 12 hours after operation. Patients in group E received combined spinal and epidural anesthesia, and when the operation was complete kept the epidural catheter and received patient-controlled epidural analgesia with an analgesia pump. RESULTS: The visual analog scores of patients at each time point in the two groups showed no significant difference (P > 0.05). Mean arterial pressure at 30 minutes after anesthesia and 4 hours postoperation in group E decreased significantly and was significantly lower than group N (P < 0.01). Group E had significantly higher rate of urinary retention than group N (P < 0.05), and the time of first food intake of patients in group N was significantly shorter than in group E (P < 0.001). CONCLUSION: For patients with unilateral lower-extremity fracture receiving internal fixation, multiple injections through catheters beside the lumbar plexus or sciatic nerve can provide adequate postoperative analgesia, with very few adverse effects.

The effects of lidocaine used in sciatic nerve on the pharmacodynamics and pharmacokinetics of ropivacaine in sciatic nerve combined with lumbar plexus blockade: a double-blind, randomized study.

In this controlled, randomized, double-blind study, we compared the pharmacodynamics and pharmacokinetics of ropivacaine and staged injection of lidocaine and ropivacaine in a combined lumbar plexus-sciatic nerve block. The experiment was performed in two parts: pharmacodynamics study (Group r, n = 20; Group lr, n = 20) and pharmacokinetics study (Group R, n = 10; Group LR, n = 10). The sciatic nerve blockade was performed using either (1) 10 mL of 2% lidocaine and then 10 mL of 0.75% ropivacaine (Group lr and Group LR) or (2) 10 mL of normal saline (N.S.) and then 10 mL of 0.75% ropivacaine (Group r and Group R). Two kinds of solutions were 'staged' injection. The sensory onset time and sensory recovery time were assessed in the pharmacodynamics study. Arterial blood samples were collected for the pharmacokinetics study. Sciatic sensory block onset times were reduced, and the sensory recovery times were decreased in Group lr. C(max) of ropivacaine in Group LR was significantly higher than that in Group R. A significant increase in AUC((0-t)) and AUC((0-∞)) was observed in Group LR compared with Group R. When 2% lidocaine and 0.75% ropivacaine are used for a combined sciatic nerve-lumbar plexus block by 'staged' injection, lidocaine induced faster onset times, decreased the block duration and increased the AUC and C(max) of ropivacaine.

[Effect of transcutaneous acupoint electrical stimulation on lipid peroxidation and cognitive function in patients experiencing craniotomy].

OBJECTIVE: To observe the effect of transcutaneous acupoint electrical stimulation (TAES) on serum superoxide dismutase (SOD) activity, malondialdehyde (MDA) and S100beta contents in craniotomy patients for studying its cerebral protection mechanism. METHODS: Fifty patients scheduled for neurosurgery were randomly divided into TAES group (n = 25) and control group (n=25) with randomized block method. For patients of TAES group, TAES was applied to bilateral Hegu (LI 4) and Quchi (LI 11), Zusanli (ST 36) and Sanyinjiao (SP 6) from 30 minutes on before anesthesia to the end of operation. Patients of control group were anesthetized with sevoflurane inhalation and intermittent (i.v.) of sulfenany and vecurnium bromide. Blood samples were taken for assaying serum SOD activity, MDA and S100beta contents with purinase oxydasis, biochemiluminescence and enzyme linked immunosorbent assay separately. Scores of cognitive ability were given by using Mini Mental State Examination (MMSE). RESULTS: In comparison with pre-anesthesia, serum SOD activity decreased significantly 1 h after craniotomy in control group, at the end of operation in both control and TAES groups (P<0.05, P<0.01), and increased markedly 48 h after operation in control group (P<0.05). Serum MDA in control group increased significantly 48 h after operation, while that in TAES group reduced apparently 24 h after operation (P<0.01). Serum S100beta content in TAES group decreased remarkably 48 h after operation (P<0.01). Serum SOD activity of TAES group was significantly higher than that of control group 24 h after operation (P<0.05). Compared with control group, serum MDA contents of 24 h and 48 h after operation and serum S100beta levels at 1 h after craniotomy and 48 h after operation were markedly lower in TAES group (P<0.01, P<0.05). No significant differences were found between two groups in the cognitive function scores (P>0.05). CONCLUSION: TAES can increase serum SOD activity and reduce MDA and S100beta levels in patients undergoing craniotomy, which may contribute to its effect in reducing lipid peroxidation induced cerebral injury. But its impact on the patient's cognitive function needs study further.

[Effect of transcutaneous acupoint electrical stimulation on blood bioactive compounds involving cerebral injury during craniotomy].

OBJECTIVE: To observe the effect of transcutaneous acupoint electrical stimulation (TAES) on plasma ET, CGRP and serum IL-6, S100beta during craniotomy. METHODS: Fifty patients scheduled for neurosurgery were randomly divided into TAES group (n=25) and control group (n=25). TAES (2/100 Hz, 8-12 mA) of bilateral Hegu (LI 4)-Quchi (LI 11), Zusanli (ST 36)-Sanyinjiao (SP 6) was administrated for patients of TAES group starting 30 min before anesthesia till the end of the operation. Anesthesia of the patients was maintained with sevoflurane inhalation and intermittent intravenous injection of boluses of sulfenany and vecurnium bromide. Jugular venous blood samples were taken at preanesthesia (T0), 1 hour after craniotomy (T1), closure complete (T2), 24 hours (T3) and 48 hours (T4) after operation respectively for detecting contents of plasma endothelin (ET), calcitonin gene-related peptide (CGRP) and serum interleukin (IL)-6, S100beta with radioimmunoassay and enzyme linked immunosorbent assay separately. RESULTS: Compared with control group, plasma ET at T2, serum IL-6 at T1 S100beta at T1 and T4 in TAES group all decreased significantly (P < 0.01, 0.05), while serum IL-6 at T3 increased remarkably (P < 0.05). It suggests that after TAES, CGRP/ET was improved, favoring cerebral microcirculation to reduce surgery-induced cerebral injury. There were no significant differences between two groups at different time courses in plasma CGRP concentrations (P > 0.05). CONCLUSION: TAES can regulate plasma CGRP/ET and serum IL-6, lower serum S100beta level, which may contribute to its effect in relieving craniotomy-induced brain injury.