Effects of gut hormones on the large bowel injury

本研究的第一个目的是观察蛙皮素(BBS)对大鼠乙酸性结肠炎的治疗作用。选用雄性Fischer 344只大鼠。在降结肠做两端结肠造口，分离大肠。用4%醋酸灌胃15s，在大肠远端诱发结肠炎。术后每隔8h皮下注射生理盐水或BBS，剂量分别为3、10、30 mg/kg，至术后第4天(POD)。术后第4天处死大鼠，切除大肠远端段。使用组织学分级标准来确定黏膜炎症反应的程度(SCand J Gasterenterol 1993；28：155-162)。评估的因素包括溃疡、粘液细胞耗竭、隐窝脓肿、炎性囊肿、粘膜萎缩、水肿、炎性细胞浸润和血管扩张。BBS能剂量依赖性地降低乙酸性结肠炎大鼠的组织学评分。本研究的第二个目的是观察BBS对直肠和小肠粘膜增殖的影响。用溴脱氧尿嘧啶核苷(BrdU)标记和未标记的细胞在增殖细胞区计数，以分析肠粘膜的标记指数。标记指数用BrdU标记的细胞数/增殖区内细胞总数表示。BBS可显著增加直肠和空肠黏膜的标记指数，并呈剂量依赖性。BBS以30 mg/kg剂量连续给药5d，可显著增加大鼠空肠重量及DNA、RNA和蛋白质含量。

The first purpose of this study was to evaluate the effect of bombesin (BBS) on acetic acid-induced colitis in rats. Male Fischer 344 rats were used. Two end colostomies were made at the descending colon to separate the large bowel. Colitis was induced in the distal segment of large bowel by administration of 4% acetic acid for 15 sec. Rats were administered subcutaneous injection of saline or BBS every 8 h at doses of 3,10 or 30 mug/kg after the operation until the 4th postoperative day (POD). Rats were sacrificed on the 4th POD and the distal segment of large bowel was excised. A histologic grading scale was used for determination of the extent of inflammatory reaction in the mucosa (Scand J Gastroenterol 1993 ; 28 : 155-162). The factors evaluated were ulceration, mucus cell depletion, crypt abscess, inflammatory cyst, mucosal atrophy, edema, inflammatory cell infiltration and vascular dilatation. Administration of BBS significantly decreased the histologic scoring of acetic acid-induced colitis in a dose-related manner.The second purpose of this study was to evaluate the effect of BBS on the proliferation of rectal and small intestinal mucosa. For analysis of the labelling index of the gut mucosa, the numbers of bromodeoxyuridine (BrdU)-labelled and unlabeled cells in the zone of proliferating cells were counted. The labelling index was expressed as the number of BrdU-labelled cells/total number of cells within the zone proliferating cells. BBS significantly increased the labelling indices of rectal and jejunal mucosa in a dose-related manner. Furthermore, administration of BBS for 5 days at the dose of 30 mug/kg significantly increased the weight and contents of DNA,RNA and protein in rat jejunum.