NMDA Receptor Antagonist MK801 Protects Against 1-Bromopropane-Induced Cognitive Dysfunction / 神经科学通报·英文版

Occupational exposure to 1-bromopropane (1-BP) induces learning and memory deficits. However, no therapeutic strategies are currently available. Accumulating evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) and neuroinflammation are involved in the cognitive impairments in neurodegenerative diseases. In this study we aimed to investigate whether the noncompetitive NMDAR antagonist MK801 protects against 1-BP-induced cognitive dysfunction. Male Wistar rats were administered with MK801 (0.1 mg/kg) prior to 1-BP intoxication (800 mg/kg). Their cognitive performance was evaluated by the Morris water maze test. The brains of rats were dissected for biochemical, neuropathological, and immunological analyses. We found that the spatial learning and memory were significantly impaired in the 1-BP group, and this was associated with neurodegeneration in both the hippocampus (especially CA1 and CA3) and cortex. Besides, the protein levels of phosphorylated NMDARs were increased after 1-BP exposure. MK801 ameliorated the 1-BP-induced cognitive impairments and degeneration of neurons in the hippocampus and cortex. Mechanistically, MK801 abrogated the 1-BP-induced disruption of excitatory and inhibitory amino-acid balance and NMDAR abnormalities. Subsequently, MK801 inhibited the microglial activation and release of pro-inflammatory cytokines in 1-BP-treated rats. Our findings, for the first time, revealed that MK801 protected against 1-BP-induced cognitive dysfunction by ameliorating NMDAR function and blocking microglial activation, which might provide a potential target for the treatment of 1-BP poisoning.

Protective effect of edaravone on central nervous system damage induced by 1-bromopropane in rats / 中国药理学与毒理学杂志

OBJECTIVE To observe the neurotoxicity of 1-bromopropane(BP) and investigate the protective effects of edaravone(Edv) against BP-induced deficits of spatial learning and memory ability in rats by its anti-inflammatory mechanism. METHODS Adult male Wistar rats were ig given BP 800 mg·kg-1 to develop the model, followed by Edv 1, 3 and 5 mg·kg-1 ip treatment respectively 4 h later for consecutive 12 d. From the 7th day (d 7), all rats were subjected to the five-day place navigation in Morris water maze (MWM) to measure the escape latency and the total swimming distance. On d 6 of MWM, spatial probe test was performed and the crossing times of rats were recorded to evaluate the spatial memory ability. At the end of the behavioral experiment, four rats in each group were randomly selected and the frozen section of the whole brain was sliced for thionin staining and immunohisto?chemistry. The other eight sacrifced rat brains from each group were harvested for the determination of the tumor necrosis factor-α (TNF-α) and nitric oxide (NO) by ELISA and nitrate reductase method, respectively. RESULTS The results of MWM test showed that compared with control rats the escape latencies of rats in BP group were increased by 60.8%, 81.9%,124.0% and 323.3%, respectively, during the d 2-d 5 of MWM, and the total swimming distance increased by 47.0%, 66.4%, 106.0% and 277.6%, respectirely. All the differences between BP group and control group were significant (P<0.05, P<0.01). In the spatial probe trial, the crossing times of rats in BP group were significantly decreased, compared with the control rats (P<0.01). Morphologically, thionin staining and immunohistochemistry revealed significant microglia activation and neuron loss in the rat forebrains, accompanied by a 147.6% and 18.7% increase in NO and TNF-α levels in rats treated with BP respectively compared with control values (P<0.05, P<0.01). After co-treatment at different dosages of Edv with BP, the escape latencies of rats in BP+Edv 5 mg·kg-1 group were decreased by 38.4%and 44.3%(P<0.01), and the total swimming distance decreased 34.5%and 43.3%(P<0.05, P<0.01), respectively, compared with the BP treated rats on the d 4 and d 5 of MWM test. The microglia activation and neuron damage in the brain of rats induced by BP treatment were significantly alleviated in BP+Edv groups. In addition, the contents of NO and TNF-α were decreased in BP+Edv 1, 3 and 5 mg · kg-1 groups, with a decrease of 53.8%, 55.4% and 59.8% in NO, and 12.2%, 15.8% and 22.2% in TNF-α(P<0.05, P<0.01), respectively. CONCLUSION Edv could effectively protect against central neurotoxicity induced by BP via anti-neuro?inflammation.

Glutamine regulates the proliferation and survival of small cell lung cancer H446 cells / 天津医药

Objective To investigate the effects of glutamine (Gln) on proliferation and survival of small cell lung cancer H446 cells, and further to explore the potential mechanism. Methods The proliferation of H446 cells was detected at different time points (0, 24, 48, 72 and 96 h) by CCK-8 assay in Gln (+) group and Gln (-) group, and an optimal time was selected. Under the optimal time, Annexin V-FITC/PI staining, CellTiter-Glo? assay kit and flow cytometer were used to detect cell survival, cellular adenosine triphosphate (ATP) and reactive oxygen species (ROS) levels. Gln (-) group was used as the control group, under the condition of Gln deficiency, cellular ATP, cell proliferation and survival were detected after adding oxaloacetic acid (OAA) or dimethyl-α-ketoglutarate (DM-αKG). Gln (-) group was used as the control group, cellular ROS, cell proliferation, colony and survival were detected after treated with ROS scavenger N- acetyl cysteine (NAC). With different concentrations (0, 2, 5, 10 μmol/L) of glutaminase inhibitor BPTES, the optimal concentration was selected through the colony assay. The cellular ATP and ROS levels and cell proliferation were detected under the optimal concentration. H446 cells were treated with bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES), ROS inducer hydrogen peroxide (H2O2) or the combination of them, and cell survival ratio was compared between two groups. Results The proliferation levels of H446 cells at 24, 48, which were decreased most significantly in 72 h in Gln (-) group. When 72 h was used as the optimal time, the cell survival ratio and ATP level were decreased, and the ROS level was increased, in Gln (-) group compared with those of Gln (+) group (P<0.05). There was a higher survival ratio in H446 cells in Gln (-)+OAA group and Gln (-)+DM-αKG group than that of Gln (-) group (P<0.05), but there were no significant differences in cell proliferation and ATP levels between Gln (-) group, Gln (-)+OAA group and Gln (-)+DM-αKG group. The ROS level was reduced, the cell proliferation, colony level and survival ratio were increased in Gln (-)+NAC group compared with those of Gln (-) group (P<0.05). Cloning assay showed that 10μmol/L was the optional concentration. Under this concentration, the proliferation and ATP level were decreased in Gln(+)+BPTES group (P<0.05), and cellular ROS level was up-regulated compared with Gln(+) group. The survival ratio was significantly lower in BPTES+H 2O2 group compared with BPTES (+) group or H2O2 (+) group. Conclusion Glutamine deficiency inhibits the proliferation and survival ratio of H446 cells through enhancing ROS level. BPTES and H2O2 show synergistically inhibitory effect on the survival of H446 cells.