Rainey J B, Maeda M, Williamson R C
Gut. 1985 Jul;26(7):718-23. doi: 10.1136/gut.26.7.718.
As the relative resistance of rat caecum to chemical carcinogens could reflect its luminal environment, caecal mucosa was exposed to the distal faecal stream in male Sprague-Dawley rats (n = 50) previously treated with azoxymethane (total dose 90 mg/kg sc). After colonic transection at the pelvic brim, the caecum was inserted isoperistaltically between colocaecal and caecorectal anastomoses (n = 30); an ileocolic anastomosis restored intestinal continuity. Controls (n = 20) had transection and reanastomosis at equivalent points of the bowel, plus caecotomy and resuture. Caecal crypt cell production rate, as determined stathmokinetically at 28 weeks, was not consistently affected by transposition. No tumors developed in either transposed or orthotopic caecum, apart from three suture-line tumours found at the caecotomy site in controls. The colonic tumour yield in controls (1.4 +/- 0.3 per rat : mean +/- SEM) matched that after transposition (1.5 +/- 0.2), but anastomotic tumours were twice as common after transposition (p less than 0.05) and rectal tumours were increased four-fold (p less than 0.05). The caecum remains resistant to carcinogenesis despite transposition to a distal colonic environment. Local epithelial defence mechanisms are more important than luminal contents in maintaining this resistance.
由于大鼠盲肠对化学致癌物的相对抗性能够反映其肠腔环境，因此将盲肠黏膜暴露于先前用氧化偶氮甲烷（总剂量90mg/kg，皮下注射）处理过的雄性Sprague-Dawley大鼠（n = 50）的远端粪便流中。在盆腔边缘进行结肠横断后，将盲肠以等蠕动方式插入结肠盲肠和盲肠直肠吻合口之间（n = 30）；回结肠吻合术恢复肠道连续性。对照组（n = 20）在肠道的相应部位进行横断和重新吻合，外加盲肠切开术和重新缝合。在28周时通过静止分析法测定的盲肠隐窝细胞产生率并未因移位而受到持续影响。除了在对照组的盲肠切开术部位发现的3个缝合线肿瘤外，移位或原位盲肠均未发生肿瘤。对照组的结肠肿瘤发生率（每只大鼠1.4±0.3：平均值±标准误）与移位后的发生率（1.5±0.2）相当，但移位后吻合口肿瘤的发生率是对照组的两倍（p<0.05），直肠肿瘤的发生率增加了四倍（p<0.05）。尽管盲肠移位至远端结肠环境，但它仍对致癌作用具有抗性。在维持这种抗性方面，局部上皮防御机制比肠腔内容物更为重要。
