BACKGROUND: Hyperbaric oxygen can reduce brain ischemic-reperfusion injury, and this effect is closely related to the modulation of hyperbaric oxygen on microglias.OBJECTIVE: To explore the influence of hyperbaric oxygen on the activity of in vitro cultured brain microglias and secretion of interleukin-1, tumor necrosis factor α and nitric oxide (NO).DESIGN: Completely randomized grouping design, control experiment.SETTING: Teaching and Research Section of Diving Medicine, Teaching and Research Section of Immunity, Teaching and Research Section of Pathology, and the Experimental Animal Center, the Second Military Medical University of Chinese PLA.MATERIALS: This experiment was carried out at the laboratory of Diving Medicine as well as Teaching and Research Section of Immunity, the Second Military Medical University of Chinese PLA, between May 1999 and January 2000. Thirty neonatal SD rats of 1-day birth age were selected for the experiment.METHODS: [1] Brain microglias from newborn SD rats were cultured with digestion method, and microglias were identified with non-specific phosphodiesterase staining and cellular immunochemical staining. [2] Primary microglias were inoculated on 48-well culture board by 2×105/well and randomized into 5 groups: control group without hyperbaric oxygen pretreatment, and hyperbaric oxygen (0.2 MPa 1 hour) pretreatment 3, 7, 10,14 days groups. Cells in groups with hyperbaric oxygen pretreatment at the above various time points were then further divided into 2 subgroups, with one added with culture medium containing bacterium lipopolysaccharide of 1 mg/L (for microglia activation), but not in the other group. [3] Interleukin-1 activity was determined using thymocyte proliferation method. The activity of tumor necrosis factor-α was assessed with L929 cell toxicity test.Nitrous acid content detected by Griess method represented NO content.[4] t-test was used to compare the differences in non-paired quantitative data between the two groups.MAIN OUTCOME MEASURES: The activity of interleukin-1 and tumor necrosis factor a and NO content in resting and evoked brain microglias in rats at various time points of hyperbaric oxygen pretreatment.RESULTS: Thirty SD rats entered the result analysis. [1] The activity of interleukin-1 and tumor necrosis factor α and NO content in resting brain microglias: The two groups did not differ obviously. [2] Interleukin-1activity and NO content in lipopolysaccharide-evoked brain microglias: They were significantly lower in 10-day and 14-day hyperbaric oxygen pretreatment groups than those in control group [10-day group: 0.409±0.014,(5.21±0.77) μnol/L; 14day group: 0.381±0.004, (4.93±1.02) μmol/L, P ＜ 0.05].[3] The activity of tumor necrosis factor α in evoked brain microglias: It was obviously lower in 14day hyperbaric oxygen pretreatment group than in control group [(51.20±1.13) %, (70.10±2.26) %, P ＜ 0.05].CONCLUSION: Pretreatment with 0.2 MPa hyperbaric oxygen can suppress the secretion of interleukin-1, tumor necrosis factor α and NO by evoked microglias, but has not obvious effects on resting microglias.

BackgroundThe etiology and pathogenesis of somatic symptom disorder are complicated， for which no effective treatment currently exists， posing a critical impact on their quality of life. ObjectiveTo analyze the current situation and development trend in domestic and foreign research on somatic symptom disorder from 2011 to 2021， and to better understand the research frontiers and hot spots in this field. MethodsOn 31 August 2022， literature on somatic symptom disorder published from January 1， 2011 to January 1， 2023 were searched in China National knowledge Infrastructure （CNKI）， Wanfang Data Knowledge Service Platform， Web of Science and PubMed， and a total of 15 035 articles were included， then the visualization analysis of the number of publications and keywords was conducted based on Microsoft Excel and CiteSpace software. ResultsIn the field of somatic symptoms disorder research from 2011 to 2021， the number of annual publications demonstrated an overall upward trend in foreign studies， and displayed a slow downward trend in domestic studies. The keyword co-occurrence network analysis revealed that the top five high-frequency keywords were "mental health" "depressive disorder" "depression" "anxiety" and "somatic symptom" in domestic studies， and were "symptom" "prevalence" "depression" "disorder" and "quality of life" in foreign studies. The burst analysis suggested that the burst terms in past five years were "somatic symptom" "syndrome" and "quality of life" in domestic studies， and were "major depressive disorder" and "outcome" in foreign studies. The clustering analysis yielded 8 clusters in domestic studies and 4 clusters in foreign studies， reflecting in the related disease， prevention and treatment protocols and epidemiological characteristics of somatic symptom disorder. ConclusionIn recent years， the publications and academic concerns regarding the research on somatic symptom disorder show an upward trend in foreign studies and are relatively inadequate in domestic studies， and both the domestic and foreign studies have been focused on the influencing factors of somatic symptom disorder. ［Funded by the Medical Health Science and Technology Project of Zhejiang Provincial （number， 2020PY064）； Medical Health Science and Technology Project of Hangzhou （number， 0020190783）］