Influence of mTOR signaling pathway on ketamine-induced injuries in the hippocampal neurons of rats.

OBJECTIVE: To explore the influences of mammalian target of rapamycin (mTOR) signaling pathway on ketamine-induced apoptosis, oxidative stress and Ca2+ concentration in the hippocampal neurons of rats. METHODS: The primary hippocampal neurons isolated from fetal Sprague Dawley rats were treated with ketamine (0, 50, 100 and 500 µM) for 4 days to observe its effect on mTOR signaling pathway and apoptosis of rat hippocampal neurons. Then, the hippocampal neurons were divided into C (Control), R (Rapamycin, an inhibitor of mTOR signaling pathway), K (Ketamine) and R + K (Rapamycin + Ketamine) groups to detect the apoptosis, reactive oxygen species (ROS) production, and Ca2+ concentration via the terminal transferase uridyl nick end labelling (TUNEL) assay, dichloro-dihydro-fluorescein diacetate (DCFH-DA) method and Fluo-3 acetoxymethyl ester (Fluo-3AM) staining, respectively. The expressions of mTOR signaling pathway and apoptosis-related proteins in hippocampal neurons were examined by qRT-PCR and Western blot. RESULTS: Ketamine could dose-dependently promote the apoptosis of rat hippocampal neurons with upregulation of p-mTOR and its downstream regulators (p-4E-BP-1 and p-p70S6K). However, ketamine-induced apoptosis in hippocampal neurons was reversed significantly by the administration of rapamycin, as evident by the decrease in expressions of pro-apoptotic proteins (Bax and cleaved Caspase-3) and the increase in anti-apoptotic protein (Bcl-2). Meanwhile, the ROS generation and Ca2+ concentration was inhibited accompanied with reduced malonildialdehyde levels but elevated superoxide and glutathione peroxidase activities. CONCLUSION: Inhibition of mTOR signaling pathway protected rat hippocampal neurons from ketamine-induced injuries via reducing apoptosis, oxidative stress, as well as Ca2+ concentration. ABBREVIATIONS: mTOR: mammalian target of rapamycin; SD: Sprague-Dawley; SPF: Specific-pathogen free; ROS: reactive oxygen species; TUNEL: terminal transferase uridyl nick end labelling; DCFH-DA: Dichloro-dihydro-fluorescein diacetate; Fluo-3A: Fluo-3 acetoxymethyl ester; NMDAR: non-competitive N-methyl-D-aspartame glutamate receptor; 4E-BP1: 4E binding protein 1; p70S6K: p70 S6 Kinase; PCR: Polymerase chain reaction; MDA: malonildialdehyde; GSH-PX: glutathione peroxidase; ANOVA: One-way Analysis of Variance.

Effects of preconditioning of electro-acupuncture on postoperative cognitive dysfunction in elderly: A prospective, randomized, controlled trial.

Electro-acupuncture is a burgeoning treatment using the needle inserting into the body acupoints and the low-frequency pulse current being electrified by an electric acupuncture machine. This study was designed to evaluate the effects of preconditioning of electro-acupuncture on postoperative cognitive dysfunction in elderly.Ninety patients scheduled spine surgery were randomly assigned into 2 groups using a random number table: control group (group C) and electro-acupuncture group (group EA). In group EA, electro-acupuncture was applied on Baihui, Dazhui, and Zusanli acupoints 30 minutes before anesthesia. At 0 minute before treatment of electro-acupuncture, 1 hour after skin incision and surgery completed (T1-3), blood samples were taken for detection of interleukin (IL)-6, IL-10, and S100ß by enzyme-linked immunosorbent assay. The total dose of remifentanil and propofol during surgery were recorded. Mini-Mental State Examination was applied to evaluate the cognitive function of patients at 1 day before surgery and 7th and 30th day after surgery.The results showed that compared with group C, score of MMSE increased after surgery, the serum concentration of IL-6, IL-10, and S100ß decreased at 1 hour after skin incision, and surgery completed in group EA. Moreover, the total dose of remifentanil and propofol reduced during surgery in group EA.The present study suggests that preconditioning of electro-acupuncture could improve the postoperative cognitive function, and the reduction of inflammatory reaction and brain injury may be involved in the mechanism.

Effects of nimodipine on postoperative delirium in elderly under general anesthesia: A prospective, randomized, controlled clinical trial.

Nimodipine is a clinical commonly used calcium antagonistscan lowering the apoptosis rate of hippocampal neuron to reduce the incidence of postoperative cognitive dysfunction (POCD). This study was designed to evaluate the effects of nimodipine on postoperative delirium in elderly under general anesthesia.Sixty patients shceduced spine surgery under general anesthesia were randomly assigned into 2 groups using a random number table: control group (Group C) and nimodipine group (Group N). In Group N, nimodipine 7.5 µg/(kg × h) was injected continually 30 minutes before anesthesia induction, while the equal volume of normal saline was given in Group C. At 0 minute before injection, 0 minute after tracheal intubation, 1 hour after skin incision and surgery completed (T1-4), blood samples were taken from the radial artery and jugular bulb for blood gas analysis. Cerebral oxygen metabolism-related indicators were calculated at the same time. Concentration of S100ß and glial fibrillary acidic protein (GFAP) were tested by ELISA. The incidence of postoperative delirium within 7 days after surgery was recorded.Cerebral oxygen metabolism-related indicators fluctuationed in the normal range in 2 groups at different time points and the difference were not statistically significant. Compared with Group C, S100ß and GFAP decreased and incidence of postoperative delirium reduced at T3-4 in Group N, the difference was statistically significant (P<.05).The present study suggests that nimodipine can reduce the development of postoperative delirium in elderly patients under general anesthesia, the reduction of brain injury and improvement of cerebral oxygen metabolism may be involved in the mechanism.

Clinical application of bupivacaine in non-catheter infiltration anesthesia during vitrectomy / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To evaluate the effect of bupivacaine in non-catheter infiltration anesthesia during vitretomy operation.·METHODS:Fifty-eight patients (58 eyes) with vitreous retinal surgery were selected. Patients were randomly divided into observation group ( 28 eyes ) and control group ( 30 eyes ) . The observation group were received non-catheter infiltration anesthesia. The control group were received traditional Sub- Tenon's block ( STB ) . Degree of pain, basic vital signs, the duration of anesthesia and analgesia grade were recorded and compared between two groups.·RESULTS: No significant difference was found in the 11-point numeric rating scale ( NRS - 11 scoring ) of anesthesia process, sclera incision, intraocular operation and the end of operation between two groups (P>0. 05). The difference were not significant in heart rate and blood pressure between two groups(P>0. 05). There was statistically significant difference in the duration of anesthesia between two groups (P<0. 05).·CONCLUSION: Both groups can provide the same anesthetic effect. Compared to STB, non - catheter infiltration anesthesia takes short time, and it is a safe and effective anesthesia methods. In addition, compare to the mixture of bupivacaine and lidocaine injection, bupivacaine injection can provide the same anesthetic effect.

Thermoset nanocomposites from waterborne bio-based epoxy resin and cellulose nanowhiskers.

Thermoset nanocomposites were prepared from a waterborne terpene-maleic ester type epoxy resin (WTME) and cellulose nanowhiskers (CNWs). The curing behaviors of WTME/CNWs nanocomposites were measured with rotational rheometer. The results show that the storage modulus (G') of WTME/CNWs nanocomposites increased with the increase of CNWs content. Observations by scanning electron microscopy (SEM) demonstrate that the incorporation of CNWs in WTME matrix caused microphase separation and destroyed the compactness of the matrix. This effect leads to the glass transition temperatures (Tg) of WTME/CNWs nanocomposites slightly decrease with the increase of CNWs content, which were confirmed by both DSC and DMA tests. The mechanical properties of WTME/CNWs nanocomposites were investigated by tensile testing. The Yong's modulus (E) and tensile strength (σb) of the nanocomposites were significantly reinforced by the addition of CNWs. These results indicate that CNWs exhibit excellent reinforcement effect on WTME matrix, due to the formation and increase of interfacial interaction by hydrogen bonds between CNWs nano-filler and the WTME matrix.

Thermoset nanocomposites from two-component waterborne polyurethanes and cellulose whiskers.

We prepared thermoset nancomposites from biomass-based two-component waterborne polyurethane (2K-WPU) and cellulose namowhiskers (CNWs). Due to the formation of hydrogen bonds, the viscosity of 2K-WPU dispersion was found to be increased with the addition of CNWs. SEM images showed "sea-island structure" corresponding to the microphase separation between CNWs nano-filler and the 2K-WPU matrix. The α-relaxation temperature (Tα) and glass transition temperature (Tg) increased with the increase of CNWs content, which was due to the formation of a rigid CNWs nano-phase acting as crosslinking points in the 2K-WPU matrix. Mechanical properties from tensile test showed Young's modulus and tensile strength of 2K-WPU/CNWs nanocomposites were reinforced by the addition of CNWs. Thermo-stability of 2K-WPU/CNWs nanocomposites decreased slightly with the increase of CNWs content, which could be attributed to the increased thermal conductivity of the material after adding CNWs.