Abstract：
The structure of the colonic wall relies on collagen, distributed within the submucosa and the muscularis externa. A recent analysis of total collagen in human ascending colon (AC) suggests that the muscularis externa is more susceptible to age-related increases in collagen among the elderly. However, it is not clear if this change also occurs in the descending colon (DC) or if the circular and longitudinal muscle layers are similarly affected in either region of colon. The aim of this study is to determine the total collagen content in the DC and its distribution between the circular muscle (CM) and taenia coli (TC) of the AC and DC of adults and compare the same with tissue from the elderly. Masson\'s trichrome and Picrosirius red were used to assess total collagen content in the AC and DC; aged 22 - 91 years. Macroscopically normal AC from 22 patients (adults: 22-60 years; 6 male, 6 female; elderly: 70 - 91 years; 6 male, 4 female) and DC from 23 patients (adults: 23-63 years; 6 male, 7 female; elderly: 66 - 88 years; 6 male, 4 female) were obtained following surgery for non-obstructed bowel cancer. The total hydroxyproline content in DC samples was also evaluated. In the DC, tinctorial staining demonstrated an increased occurrence of total collagen fibres in the submucosa of the elderly (159.8 ± 9.6 in elderly vs. 126.9 ± 6.1 in the adults; p 0.05) and in the muscularis externa (respectively 37.4 ± 4.1 vs. 18.8 ± 2.4; p 0.01). In the adult AC and DC, there were no statistically significant differences in the amount of collagen within the CM and TC. In the elderly, the total collagen fibres within the TC was greater in the AC (mean grey intensity: 63.4 ± 3.9% in the elderly vs. 36.6 ± 1.6% in adults; p 0.05) and DC (mean grey intensity: respectively, 59.82 ± 2.4 vs. 40.2 ± 0.9%; p 0.05). In both AC and DC of the elderly samples, several thickened collagen fibrils were microscopically identified within the TC infiltrating to the myenteric plexus. In the TC of the elderly AC, the total collagen fibres were increased by approximately 4% compared to that of the DC. The total collagen concentration in the elderly DC assessed by hydroxyproline assay was increased by approximately 15% compared to the adult. Sex related differences were not found when data combined. We concluded that the total collagen content in the muscularis externa particularly of the TC of human colon increases with age. The subtle change in collagen distribution with age between AC and DC may differentially affect the tensile strength of the colon.
摘要：
结肠壁的结构依赖于胶原蛋白，分布在粘膜下层和外肌层。最近对人类升结肠（AC）中总胶原蛋白的分析表明，外部肌层更容易受到老年人与年龄相关的胶原蛋白增加的影响。然而,尚不清楚这种变化是否也发生在降结肠（DC）中，或者在结肠的任一区域中圆形和纵向肌肉层是否也受到类似影响。这项研究的目的是确定DC中的总胶原蛋白含量及其在成年人的AC和DC的环肌（CM）和taeniacoli（TC）之间的分布，并将其与老年人的组织进行比较。使用Masson三色和Picrosirius红评估AC和DC中的总胶原蛋白含量；年龄22-91岁。来自22名患者的宏观正常AC（成人：22-60岁；6名男性，6名女性；老年人：70-91岁；6名男性，4名女性）和23名患者的DC（成人：23-63岁；6名男性，7名女性；老年人：66-88岁；6名男性，4名女性）是在非阻塞性肠癌手术后获得的。还评估了DC样品中的总羟脯氨酸含量。在DC,着色染色显示老年人粘膜下层中总胶原纤维的发生率增加（老年人的159.8±9.6与成人126.9±6.1；p0.05）和外肌层（分别为37.4±4.1与18.8±2.4；p0.01）。在成人交流和直流中，CM和TC内胶原量无统计学差异。在老年人中,在AC中，TC内的总胶原纤维更大(平均灰色强度：63.4±3.9%，老年人成人36.6±1.6％；p0.05）和DC（平均灰色强度：59.82±2.4vs.40.2±0.9%；p<0.05）。在老年人样本的交流和直流中，显微镜下在浸润到肌间神经丛的TC内发现了几种增厚的胶原纤维。在老年人AC的TC中，与DC相比，总胶原纤维增加了约4％。通过羟脯氨酸测定评估的老年DC中的总胶原浓度与成人相比增加了约15%。数据合并后未发现性别相关差异。我们得出的结论是，人结肠外肌层特别是TC的总胶原蛋白含量随年龄增长而增加。AC和DC之间胶原分布随年龄的细微变化可能不同地影响结肠的拉伸强度。
