This study assessed the impact of administering vasoactive intestinal polypeptide (VIP) on inflammation and intestinal VIP and tight junction mRNA expression in lambs fed grain-based finishing diets. Sixteen wether lambs (69.6 ± 1.9 kg) were individually housed, adapted to a corn-based diet containing no forage, and randomly assigned to 2 treatment groups. Lambs were intraperitoneally injected every other day for 28 d with either saline (0.9% NaCl) with no VIP (n = 8; control) or saline with VIP (n = 8; 1.3 nmol/kg BW). Blood samples were collected weekly for analysis of cytokine concentrations, and on day 0 and 28 for lipopolysaccharide (LPS), and LPS binding protein (LBP) concentrations. Upon completion of the treatment period, lambs were euthanized and gastrointestinal tissues, including rumen, jejunum, cecum, and colon samples, collected for analysis of the expression of tight junction mRNA (claudin-1, claudin-4, occludin, and ZO-1), endogenous VIP, and VIP receptor (VPAC-1). No treatment effects (P ≥ 0.38) were observed for VIP and VPAC-1 mRNA expression in colon. Supplementation with VIP did not influence (P ≥ 0.28) the expression of claudin-1, claudin-4, occludin, and ZO-1 tight junction mRNA in the rumen, jejunum, cecum, and colon. Lambs treated with VIP had greater (P ≤ 0.01) plasma concentrations of the anti-inflammatory cytokines, IL-10 and IL-36RA. There were treatment by day interactions observed (P ≤ 0.02) for concentrations of the proinflammatory cytokines, MIP-1α and MIP-1β. Lambs that did not receive VIP had greater serum concentrations of LPS (P = 0.05) than the lambs receiving VIP. These data suggest that VIP administration may not influence tight junction mRNA expression but may decrease LPS concentrations and thus inflammation in lambs fed a grain-based diet.

中文翻译：

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外源性血管活性肠多肽 （VIP） 对饲喂高谷物饮食羔羊炎症反应和紧密连接基因 mRNA 表达的影响


本研究评估了施用血管活性肠多肽 （VIP） 对饲喂以谷物为基础的育肥日粮的羔羊炎症和肠道 VIP 和紧密连接 mRNA 表达的影响。将 16 只湿羔羊 （69.6 ± 1.9 kg） 单独饲养，适应不含饲料的玉米饮食，并随机分配到 2 个处理组。每隔一天给羔羊腹腔注射 28 天，注射不含 VIP 的生理盐水 （0.9% NaCl） （n = 8;对照） 或含 VIP 的生理盐水 （n = 8;1.3 nmol/kg BW）。每周采集血样用于分析细胞因子浓度，并在第 0 天和第 28 天采集脂多糖 （LPS） 和 LPS 结合蛋白 （LBP） 浓度。治疗期结束后，对羔羊实施安乐死，并收集胃肠道组织，包括瘤胃、空肠、盲肠和结肠样本，用于分析紧密连接 mRNA （claudin-1、claudin-4、occludin 和 ZO-1）、内源性 VIP 和 VIP 受体 （VPAC-1） 的表达。未观察到结肠中 VIP 和 VPAC-1 mRNA 表达的治疗效果 （P ≥ 0.38）。补充 VIP 不影响 （P ≥ 0.28） 瘤胃、空肠、盲肠和结肠中 claudin-1 、 claudin-4、occludin 和 ZO-1 紧密连接 mRNA 的表达。VIP 处理的羔羊血浆抗炎细胞因子 IL-10 和 IL-36RA 浓度较高 （P ≤ 0.01）。观察到促炎细胞因子 MIP-1α 和 MIP-1β 浓度的日间相互作用 （P ≤ 0.02）。未接受 VIP 的羔羊的血清 LPS 浓度 （P = 0.05） 高于接受 VIP 的羔羊。 这些数据表明，VIP 给药可能不会影响紧密连接 mRNA 表达，但可能会降低 LPS 浓度，从而降低以谷物为基础的饮食喂养的羔羊的炎症。