Thomas J Regan
Department of Otolaryngology, Chicago, Illinois, USA.
Laryngoscope. 2005 Mar;115(3):405-11. doi: 10.1097/01.mlg.0000157845.86154.48.
OBJECTIVE/HYPOTHESIS: To document age-related histologic morphometric changes of rat skin and the effects of calorie restriction on such changes.
Fischer 344 rats of three age groups (young, 4 mo; adult, 1 year; old, 24+ months) were procured from ad libitum (AL) diet and calorie-restricted (CR) colonies of the National Institute of Aging and were used for histologic study. Each study group consisted of six animals.
Skin samples from the dorsum (DS) and footpad (FP) of these animals were excised and processed for histology with staining techniques for general morphology (hematoxylin-eosin-phloxine) and for differentiation of collagen bundles and elastic fibers (Verhoeff-van Gieson technique). Light microscopic morphometric and stereologic point counting procedures were applied manually to tissue sections to obtain quantitative data on the depth of the epidermis, dermis, and stratum corneum, epidermal nuclear number, and percentage fraction of collagen, elastic fibers, capillaries, and pilosebaceous units. Data were analyzed with two-way of analysis of variance (ANOVA) to determine significant effects of age, diet, and age-diet interaction on these parameters in AL rats and their age-matched cohorts.
Significant effects of age, diet, or age-diet interaction were observed in respect of the thickness of epidermis, dermis, stratum corneum of FP, epidermal nuclear number, collagen percentage fraction, and area fraction of capillaries. DS epidermis showed increasing thickness in AL group, but this was reduced in CR rats. A similar trend in DS dermal depth was observed. Fewer capillaries were present in aging CR rats. The DS epidermal nuclear profiles and collagen area fraction also showed effects of diet and age-diet interaction. Aging changes, especially the effect of CR, was more evident in the measured parameters of dorsal skin. No alterations were observed in the distribution of pilosebaceous units and elastic fiber profiles of the skin.
The Fischer 344 rat shows many age-related changes in the skin, some of which are different from data reported in literature. The pattern of aging changes in skin parameters was different in the two groups, suggesting an in influence of CR. CR appears to modify the aging rate of some skin components, and this may be caused by metabolic changes imposed by diet.
目的/假设：记录大鼠皮肤与年龄相关的组织学形态测量变化以及热量限制对此类变化的影响。
从美国国立衰老研究所的自由摄食（AL）组和热量限制（CR）组获取三个年龄组（幼年，4个月；成年，1岁；老年，24个月以上）的Fischer 344大鼠，用于组织学研究。每个研究组由六只动物组成。
切除这些动物背部（DS）和足垫（FP）的皮肤样本，采用苏木精-伊红-派洛宁染色技术进行一般形态学组织学处理，采用Verhoeff-van Gieson技术进行胶原束和弹性纤维的分化处理。对组织切片手动应用光学显微镜形态测量和体视学点计数程序，以获取有关表皮、真皮和角质层深度、表皮细胞核数量以及胶原、弹性纤维、毛细血管和毛囊皮脂腺单位的百分比分数的定量数据。采用双向方差分析（ANOVA）对数据进行分析，以确定年龄、饮食以及年龄-饮食相互作用对AL组大鼠及其年龄匹配队列中这些参数的显著影响。
在表皮、真皮、FP角质层厚度、表皮细胞核数量、胶原百分比分数和毛细血管面积分数方面观察到年龄、饮食或年龄-饮食相互作用的显著影响。DS表皮在AL组中厚度增加，但在CR大鼠中厚度减小。在DS真皮深度方面观察到类似趋势。衰老的CR大鼠中毛细血管较少。DS表皮细胞核轮廓和胶原面积分数也显示出饮食和年龄-饮食相互作用的影响。衰老变化，尤其是CR的影响，在背部皮肤的测量参数中更为明显。未观察到皮肤毛囊皮脂腺单位分布和弹性纤维轮廓的改变。
Fischer 344大鼠皮肤显示出许多与年龄相关的变化，其中一些与文献报道的数据不同。两组皮肤参数的衰老变化模式不同，表明CR有影响。CR似乎改变了一些皮肤成分的衰老速率，这可能是由饮食引起的代谢变化导致的。
