灸预处理对乙醇诱导胃黏膜损伤大鼠TLR4、MyD88、NF-κB p65蛋白的影响

目的 观察灸预处理对乙醇诱导大鼠胃黏膜损伤的影响，探讨灸法对胃黏膜损伤“未病先防”的作用机制。方法 将大鼠随机分为正常组、模型组和灸预处理组，每组10只，先对灸预处理组大鼠进行艾灸“足三里”“中脘”，再对模型组和灸预处理组大鼠进行乙醇灌胃制备胃黏膜损伤模型。比较各组大鼠胃黏膜溃疡指数（ulcer index,UI）和病理学变化，ELISA法检测大鼠血清肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）和白细胞介素-6 (interleukin- 6，IL-6)水平，免疫组织化学法和Western blot法检测胃黏膜组织Toll样受体4（Toll-like receptor 4，TLR4）、髓样分化因子88（myeloid differentiation factor 88，MyD88）、核转录因子-κB（nuclear factor kappa B，NF-κB）p65蛋白表达水平。结果 模型组大鼠UI显著高于正常组，灸预处理组UI显著低于模型组（P＜0.05），模型组大鼠胃黏膜上皮结构破坏严重，有出血灶和炎症细胞浸润；灸预处理组大鼠胃黏膜病理损伤低于模型组；与正常组比较，模型组和灸预处理组大鼠血清TNF-α、IL-6水平均显著升高（P＜0.05），胃黏膜组织TLR4、MyD88表达水平均显著升高（P＜0.05）；与模型组比较，灸预处理组各项指标均显著降低（P＜0.05）。结论 灸预处理对胃黏膜具有保护作用，其机制可能是通过调控TLR4、MyD88、NF-κB p65蛋白表达水平实现的。     

Preventing construction deaths: The role of public policies

Are stronger direct financial incentives or regulatory enforcement effective in reducing fatalities in the construction industry? We examine two important policies—state workers' compensation (WC) programs and federal and state Occupational Safety and Health Administration (OSHA) activities—which embody those strategies. We examine their impact by looking at state-level fatality rates in the construction industry from 1992 to 2016. Setting aside highway crashes and violence, the majority of employee deaths occur in construction. We find that states which exempt small firms from the requirement to buy WC insurance have higher fatality rates. When eligibility for compensation is restricted by longer waiting periods, fatality rates are substantially higher. More frequent federal or state OSHA inspections and, especially, consultation visits are associated with lower fatality rates, but higher average penalties are not. Limited variation in these policies over our sample period, especially for WC, makes these results suggestive rather than definitively causal.