University of Roehampton, School of Life and Health Sciences. Holybourne Ave, London. SW15 4JD, UK.
Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
Acta Histochem. 2022 Dec;124(8):151958. doi: 10.1016/j.acthis.2022.151958. Epub 2022 Oct 6.
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.
结肠壁的结构依赖于胶原蛋白，分布于黏膜下层和外肌层。最近对人类升结肠（AC）总胶原的分析表明，外肌层在老年人中更容易受到与年龄相关的胶原增加的影响。然而，目前尚不清楚这种变化是否也发生在降结肠（DC）中，或者在结肠的任何区域，环形和纵向肌肉层是否受到同样的影响。本研究旨在确定 DC 中的总胶原含量，并比较其在 AC 和 DC 的环形肌（CM）和结肠带（TC）中的分布，并将其与老年人的组织进行比较。马松三色和苦味酸天狼星红被用于评估 AC 和 DC 中的总胶原含量；年龄 22-91 岁。22 名接受非梗阻性肠癌手术的患者的 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）的 DC 获得。还评估了 DC 样本中的总羟脯氨酸含量。在 DC 中，染色显示老年人黏膜下层总胶原纤维的发生率增加（老年人为 159.8±9.6，成年人为 126.9±6.1；p<0.05）和外肌层（分别为 37.4±4.1 和 18.8±2.4；p<0.01）。在成人 AC 和 DC 中，CM 和 TC 内的胶原含量没有统计学上的显著差异。在老年人中，TC 内的总胶原纤维在 AC 中更大（平均灰度强度：63.4±3.9%在老年人中 vs. 36.6±1.6%在成年人中；p<0.05）和 DC（平均灰度强度：分别为 59.82±2.4%和 40.2±0.9%；p<0.05）。在老年人样本的 AC 和 DC 中，在 TC 内观察到几处增厚的胶原纤维，向肌间神经丛浸润。在老年人 AC 的 TC 中，总胶原纤维比 DC 增加了约 4%。用羟脯氨酸测定法评估的老年人 DC 中的总胶原浓度比成人增加了约 15%。当数据合并时，没有发现性别相关的差异。我们得出结论，人类结肠外肌层，特别是 TC 的总胶原含量随年龄增长而增加。AC 和 DC 之间胶原分布的细微变化可能会对结肠的拉伸强度产生不同的影响。
