银杏苦内酯B对内毒素血症幼年大鼠肠氧化损伤的保护作用

 目的 氧化应激与炎性反应引起的肠组织损伤密切相关。应用血小板活性因子（PAF）受体拮抗剂银杏苦内酯B对幼年大鼠内毒素血症模型中肠黏膜氧化损伤的保护作用作初步研究。方法 18 d Wistar大鼠，随机分为内毒素脂多糖（LPS）组和PAF受体拮抗剂组（预防组和治疗组）及对照组，注射LPS后1.5，3，6，24，48，72 h取回肠。LPS组和对照组分别腹腔注射内毒素5 mg/kg及生理盐水1 mL/kg；预防组和治疗组分别于每一时相点注射LPS 前、后30 min腹腔注射PAF受体拮抗剂（银杏苦内酯B）BN52021 5 mg/kg。苏木精-伊红染色及透射电镜作形态学检查，剩余部分回肠于-80℃深低温冰箱中保存，检测黄嘌呤氧化酶(XOD)、超氧化物歧化酶（superoxide dismutase，SOD）。结果 1.5，3，6，24 h LPS组可见绒毛水肿，固有层血管充血，间质淋巴管扩张，肠腔炎性渗出，拮抗剂组可见绒毛水肿。电镜下对照组肠微绒毛及细胞间紧密连接未见异常。实验组上皮细胞连接增宽；微绒毛变细、稀疏，部分断裂、脱落；细胞器受损。拮抗剂组改变较实验组减轻。LPS组1.5，3，6，24 h XOD明显高于对照组，6 h从239.85±17.64 U/gprot升至330.99±61.73 U/gprot，P＜0.01，预防组及治疗组XOD 变化趋势同LPS组，但各时相点XOD较LPS组略低。LPS组1.5，3，6，24，48 h SOD 较对照组明显降低，6 h从（141.55±28.12）U/mgprot降至（86.89±9.99 ）U/mgprot，P＜0.01，预防组及治疗组SOD 变化趋势同LPS组，但各时相点SOD较LPS组高。 结论 氧化损伤在内毒素血症肠损伤中发挥一定作用，预防和治疗性应用银杏苦内酯B BN52021可减轻肠道的炎性反应，对肠黏膜损伤具有一定的保护作用。

The Protective Effect of Ginkgolide B on Intestinal Oxidative Injury in Young Rats with Endotoxemia

Objective Oxidative stress is closely correlated with intestinal injury induced by inflammatory response.We investigated the protective effect of platelet activating factor receptor antagonist(Ginkgolide B,BN52021) on oxidative injury of intestinal in young rat with endotoxaemia.Methods Eighteen-day-old Wistar rats were randomly divided into 3 groups and treated with lipopolysaccharide(LPS)(5 mg/kg),LPS plus PAF receptor antagonist and normal saline injection(Control) respectively.Ginkgolide B 5 mg/kg was administered before or 30 minutes after LPS injection(pretreatment or treatment).The ileum specimens(n =8) were harvested at 1.5,3,6,24,48 and 72 h after LPS injection.Hematoxylin and erosin staining and transmission electron microscopy(TEM) was used for histological morphology evaluation.The rest samples were stored in-80 ℃ for measurements of xanthine oxidase(XOD) and superoxide dismutase(SOD).Results Histologic examination of intestinal injury in LPS group showed edema of the villus,capillary congestion of the lamina propria,extension of the subepithelial,polymorphonuclear infiltration in enteric cavity on 1.5,3,6,24 h.Edemas of the villus were found in antagonist group.Ultramicrostructural change of TEM showed microvilli and tight junctions were intact in the control group.Enlargement of tight junctions were seen in the experiment group,and the microvilli were thin,rare or disrupt,shed.The rough endoplasmic reticulum,mitochondria,and glycogen particles were injured.The levels of XOD at 1.5,3,6,24 h were obviously higher in LPS group than control group.The content of XOD increased mostly at 6 h from(239.85±17.64)U/g to(330.99±61.73)U/g of control group(P < 0.01).The tendency of antagonist group was the same as the LPS group.But the levels of XOD of antagonist group were lower than LPS group at each time point.The levels of SOD of 1.5,3,6,24 and 48 h were obviously decreased in LPS group compared with control group,statistic significances were found.The content of SOD decreased from(141.55±28.12)U/mg to(86.89±9.99)U/mg of control group at 6 h(P < 0.01).The tendency of antagonist group was the same as that of LPS group.But the levels of SOD of antagonist group were higher than LPS group at each point.Conclusions Oxidative damage plays a role in intestinal injury during endotoxemia.Preventive and remedial application of PAF receptor antagonist(Ginkgolide B) may relieve intestinal inflammatory response,and have a protective effect on intestinal mucosal injury.