银莱汤对胃肠积热合并肺炎大鼠胃肠动力的作用及机制研究

目的 制作胃肠积热合并肺炎模型,观察银莱汤对胃肠积热合并肺炎大鼠胃排空及小肠推进率的影响,通过检测血清中胃饥饿素（Ghrelin）、NO含量变化,初步探讨银莱汤调节胃肠动力的具体机制。方法 将实验大鼠分为正常组、胃肠积热组、胃肠积热合并肺炎组和银莱汤治疗组共4组,每组10只。其中胃肠积热组、胃肠积热合并肺炎组和银莱汤治疗组给予高热量饲料喂养,并结合52%牛奶溶液灌胃的方法制作食积动物模型,且后2组采用0.5 mg/mL LPS吸入雾化处理,并予以生理盐水或银莱汤灌胃相应的干预。采集大鼠宏观表征,行胃排空和小肠推进实验,并用Elisa法测定各组大鼠血清中Ghrelin、NO含量。结果 与正常组相比,胃肠积热组大鼠的活动度较差,摄食量减少,体质量显著降低（P<0.05）;与胃肠积热合并肺炎组相比,银莱汤治疗组大鼠胃排空和小肠推进率明显增加（P<0.05）;与胃肠积热合并肺炎组相比,银莱汤治疗组大鼠血清的Ghrelin有所升高,且NO含量明显降低（P<0.05）。结论 胃肠积热和肺炎因素会影响胃肠道内相关激素的分泌,从而导致其胃排空和小肠推进率的异常,而银莱汤能够通过升高血清中Ghrelin含量,并能抑制NO的激素水平,来达到促进胃肠动力作用。     

Ghrelin对大鼠胃黏膜上皮细胞中H~+-K~+-ATP酶基因表达和活性的影响

为揭示Ghrelin对胃酸分泌的作用,从断奶大鼠中分离新鲜胃黏膜,培养胃黏膜上皮细胞,培养30 h后,试验组培养液更换为分别含有1×10-4 μmol/L、1×10-3 μmol/L、1×10-2 μmol/L和1×10-1 μmol/L Ghrelin的新鲜培养液,对照组换为不含Ghrelin的正常新鲜培养液.继续培养4 h后,收集培养液和细胞,分别测定细胞中H+-K+-ATPase mRNA表达和活性.结果表明:1×10-3 μmol/L Ghrelin可显著增加细胞中H+-K+-ATPase mRNA的表达(P＜0.05),1×10-4 μmol/L、1×10-3 μmol/L和1×10-2 μmol/L Ghrelin明显增加了胃黏膜上皮细胞中H+-K+-ATPase的活性.这表明Ghrelin体外作用于胃黏膜上皮细胞可刺激胃酸的分泌.     

Ghrelin在成年皖西白鹅小肠内的免疫组化定位研究

采用免疫组化SABC法并结合DAB显色技术研究了皖西白鹅小肠内Ghrelin阳性细胞及其分布。结果：①Ghrelin免疫阳性细胞主要位于小肠的黏膜层，而黏膜下层和肌层未见Ghrelin阳性细胞。这些阳性细胞，胞浆着色，主要有两类，一类为“闭合型”细胞，呈圆形或椭圆形，其顶部不露于腔面，另一类为“开放型”细胞，呈锥体型，细胞顶部达到腔面。②在十二指肠，“开放型”和“闭合型”两种阳性细胞均可观察到，而在空肠和回肠，主要为“闭合型”阳性细胞。产生Ghrelin的细胞在成年皖西白鹅小肠黏膜层有广泛的分布，揭示Ghrelin可能调节小肠的功能。     

Ghrelin在哺乳动物免疫系统中的作用研究进展

Ghrelin是一种具有多种生物学功能的生长激素释放肽,近年来其在哺乳动物免疫系统中的作用研究日益丰富,而在禽类免疫系统中的研究相对较少。论文就Ghrelin在调节哺乳动物淋巴细胞增殖、细胞因子分泌、炎症及组织损伤等方面的研究进展进行了综述,同时将禽类Ghrelin在免疫系统中的研究与之进行比较,为深入探索禽类Ghrelin在免疫系统中的功能及机制提供参考。     

A study on ghrelin and LH secretion after short fasting and on ghrelin levels at perioestrual period in dairy cattle

In two experiments, we studied (a) the changes of LH secretion in heifers under different feeding schedules and (b) total ghrelin concentration at oestrus in cows and heifers. In experiment one, synchronized heifers were allocated in three groups (R, regularly fed controls; F, fasted; and F‐F fasted‐fed). One day after the completion of the oestrous induction protocol, group F and F‐F animals stayed without feed for 24 hr; thereafter, feed was provided to R and F‐F cattle; 2 hr later, GnRH was administered to all animals. Blood samples were collected for ghrelin, progesterone, LH and cortisol concentrations. Fasting caused increased ghrelin concentrations in groups F and F‐F, while in response to GnRH, LH surge was significantly attenuated in groups F and F‐F compared to R. In experiment 2, lactating cows and heifers were used. On day 9 of a synchronized cycle, PGF2α was administered, and blood samples were collected twice daily until the third day after oestrus and analysed for progesterone, estradiol, ghrelin, glucose and BHBA concentrations. No difference was recorded between groups in steroids and BHBA concentrations. In comparison to mid‐luteal values, ghrelin concentrations significantly increased at perioestrual period in cows, but not in heifers. This study provides evidence that starving‐induced elevated ghrelin concentrations can have suppressing effect on LH secretion, even after ghrelin's restoration to basal values and that during oestrus, ghrelin secretion is differently regulated in cows and heifers, likely being independent from oestradiol concentrations. Further research is required to identify the determining factors that drive the different regulation of ghrelin secretion in cows and heifers.     

Role for des-acyl ghrelin in the responsiveness of plasma hormones and metabolites to ghrelin in Holstein steers

Gastric-derived peptide hormone ghrelin is known for its potent growth hormone (GH) stimulatory effects. The acyl-modification on N-terminal Ser(3) residue is reported to be important to stimulate the ghrelin receptor, GH secretagogue-receptor type1a (GHS-R1a). However, major portion of circulating ghrelin lacks in acylation, and some biological properties of des-acyl ghrelin have been reported in monogastric animals. In the present study, the responsiveness of plasma hormones and metabolites to ghrelin in steers was characterized, and role for des-acyl ghrelin in these changes was investigated. The repeated intravenous administrations of bovine ghrelin (1.0 microg/kg BW) every 2h for 8h to Holstein steers significantly increased the plasma acylated ghrelin, total ghrelin, GH, insulin and NEFA levels. The GH responses in peak values and area under the curves (AUCs) were attenuated by repeated injections of ghrelin, however, the responses of plasma total ghrelin were similar. Plasma insulin AUC decreased after fourth injection of ghrelin while plasma NEFA AUCs gradually increased by repeated injections of ghrelin. Pretreatment of des-acyl ghrelin (10.0 microg/kg BW) 5 min prior to the single injection of ghrelin (1.0 microg/kg BW) did not affect the ghrelin-induced hormonal changes. Moreover, the responses of plasma GH to bovine and porcine ghrelin, which differ in C-terminal amino acid residues, were similar in calves. These data show that (1) GH release was attenuated by repeated administration of ghrelin, (2) ghrelin regulates glucose and fatty acid metabolism probably via different pathway, and (3) des-acyl ghrelin is unlikely the antagonist for ghrelin to induce endocrine effects in Holstein steers.     

The effects of ghrelin on ovary histology in Barbus sharpeyi

Ghrelin is expressed in key cells of the female reproductive organ in several species of fishes. It has a role in the control of fertility. In the present study, the histological effect of ghrelin on 48 female Barbus sharpeyi was tested. Twenty-four hours later, microscopic observations and histometric counting was done. The results indicated that ghrelin can increase the number of mature ovarian follicles and sexual maturation and reduce the average oocyte diameter.