摘要
目的观察谷氨酰胺(Gln)对内毒素血症新生幼鼠模型肠黏膜的保护作用。方法 4窝清洁级SD母鼠及其新生幼鼠随机分为蛋氨酸亚砜胺(MS)+生理盐水(NS)组(母鼠和幼鼠给予MS+幼鼠给予NS)、MS+Gln组(母鼠和幼鼠给予MS+幼鼠给予Gln)、正常喂养+Gln组(幼鼠正常母乳喂养+幼鼠给予Gln)和正常喂养+NS组(幼鼠正常母乳喂养+幼鼠给予NS)。各组干预均从母鼠分娩第3天和幼鼠出生第3天起开始,连续给予6d。实验第7天,各组幼鼠均腹腔注射LPS,6h后处死,测定血浆Gln浓度,肠上皮细胞膜脂质流动性及IL-1、TNF-α、MCP-1的水平,光镜、扫描电镜和透射电镜下观察肠黏膜绒毛结构的改变。结果①MS+Gln组、MS+NS组、正常喂养+Gln组和正常喂养+NS组出生幼鼠分别为11、11、10和11只,MS+Gln组和MS+NS组在实验结束前分别死亡2(18.2%)和6只(54.5%)。②MS+Gln组、MS+NS组、正常喂养+Gln组和正常喂养+NS组:体重增加量分别为(1.52±0.64)、(0.58±0.77)、(11.72±1.03)和(11.80±1.45)g,血浆Gln浓度分别为(394.3±92.5)、(105.9±37.9)、(774.6±143.7)和(676.8±113.6)μmol·L-1,肠上皮细胞膜荧光偏振度分别为(0.241±0.046)、(0.297±0.033)、(0.215±0.052)和(0.211±0.049),MCP-1水平分别为(8.0±1.6)、(5.8±0.8)、(8.5±1.3)和(8.7±1.2)pg·mL-1,TNF-α水平分别为(2.2±0.8)、(1.3±0.4)、(2.8±1.0)和(2.5±1.1)pg·mL-1,IL-1β水平分别为(28.5±15.5)、(16.8±11.0)、(31.4±15.1)、(32.3±13.9)pg·mL-1;组间总体比较差异均有统计学意义(均P<0.05)。③光镜下可见:MS+NS组和MS+Gln组肠黏膜绒毛均有不同程度变短,排列杂乱,黏膜结构破坏,以MS+NS组程度更重;正常喂养+Gln组和正常喂养+NS组肠黏膜绒毛亦有不同程度的排列紊乱和变短,但较MS+Gln组损伤程度轻。④电镜下可见:MS+NS组和MS+Gln组均有肠黏膜微绒毛排列杂乱,长度缩短,断裂明显,肠上皮细胞绒毛膜欠完整,以MS+NS组程度更重;正常喂养+Gln组及正常喂养+NS组肠黏膜微绒毛长度正常均一,排列较整齐,少见断裂,无明显脱落,肠上皮细胞膜相对完整,无明显线粒体肿胀。结论 Gln缺乏可造成新生幼鼠肠黏膜形态结构和功能改变,补充Gln可保护内毒素血症新生幼鼠的肠道形态结构和功能。
Objective To study the protective effects of glutamine（Gln） on intestinal mucosa in lipopolysaccharide-induced newborn rats.Methods Four broods of mother and infant rats were randomized into four groups： methionine sulfoximine（MS）＋Gln group： Gln-deprived pups ＋ Gln supplementation ;MS＋NS group： Gln-deprived pups without Gln supplementation; Normally fed and Gln group： normally fed pups ＋ Gln supplementation; Normally fed and NS group： normally fed pups without Gln supplementation; MS,NS and Gln were given by intraperitoneal injection for 6 days. All pups received lipopolysaccharide （LPS） on D7 and were sacrificed 6 hours later. Small intestine was harvested for studies. Plasma Gln concentration was detected by high efficiency liquid chromatography. IL-1, TNF-α and MCP-1 levels were determined with homogenate by ELISA. The intestines were examined under both light, transmission and scanning electron microscopy （EM） and membrane fluidity was determined with fluorescent polarization, using a DPH probe.Results ①The number of pups in 4 groups was 11, 11, 10 and 11 respectively, but when the experiment was finished,the number was 9, 5, 10 and 11 respectively. ②Pups weight gain （g）, plasma Gln concentration（μmol·L-1）, IEC membrane fluorescence polarization and cytokine expression （MCP-1, TNF-α, IL-1β pg·mL-1）of four groups were（1.52±0.64）,（0.58±0.77）,（11.72±1.03）and （11.80±1.45）,（394.3±92.5）,（105.9±37.9）,（774.6±143.7）and （676.8±113.6）,（0.241±0.046）,（0.297±0.033）,（0.215±0.052）and （0.211±0.049）,（8.0±1.6）、（5.8±0.8）、（8.5±1.3）and（8.7±1.2）,（2.2±0.8）,（1.3±0.4）,（2.8±1.0）and （2.5±1.1）,（28.5±15.5）,（16.8±11.0）,（31.4±15.1）and（32.3±13.9）. Overall, the between-group differences were statistically significant（P0.05）.③Under light microscopy,the intestinal structure of MS＋NS group pups was not intact, small intestine villi were the shortest and badly destroyed under optical microscopy. In MS＋Gln group,the intestinal structure was also not intact, small intestine villi were shortened and destroyed, but some of them were restored. In normal＋Gln and normal＋NS group, small intestine villi were slightly destroyed. ④Under transmission EM and scanning EM, the small intestine microvilli of MS＋NS group pups were shortest, badly abrupt and disorderly arranged, the membranes were destroyed and mitochondria were obviously ruptured. In MS＋Gln group, small intestine microvilli were shorter and disorderly arranged, the membranes were destroyed and mitochondria were obviously swollen. In normal＋Gln and normal＋NS group, small intestine microvilli were normally arranged and not obviously ruptured, the membranes were not destroyed.Conclusions Gln deprivation adversely affected gastrointestinal structure and function of newborn rats. Glutamine supplementation was protective against the damage of the gastrointestinal tract caused by endotoxemia.
出处
《中国循证儿科杂志》
CSCD
2012年第6期459-464,共6页
Chinese Journal of Evidence Based Pediatrics
基金
上海市自然科学基金:062R14017
卫生部国家临床重点专科建设项目
