Castillo-Mariqueo Lidia, Alveal-Mellado Daniel, Giménez-Llort Lydia
Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain.
Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain.
Animals (Basel). 2025 Feb 12;15(4):521. doi: 10.3390/ani15040521.
The state of frailty is a clinical-biological syndrome that affects the older population with a higher risk of functional dependence. Animal models can provide a tool to study this complex scenario. In the present work, we analyzed the physical and behavioral hallmarks of end-point status in 16-month-old mice (C57BL/6J) according to animal welfare regulations compared to age-matched counterparts with normal aging. A group of 6-month-old mice was added to control for age bias. First, we identified 'structural kyphosis' (visible and unmodifiable deformation in locomotion) correlated with piloerection as the hallmarks of the physical frailty phenotype compared to the 'postural kyphosis' (adjustment to counteract increased visceral volume but attenuated during locomotion) of old mice with normal aging. Alopecia (barbering) was presented in both old groups. Normal levels of exploratory activity in the corner test for neophobia and triceps surae muscle weight but an increased latency of rearing indicated the poorest emotional phenotype, with a possible contribution of structural kyphosis. The presence of hepatomegaly and splenomegaly counteracted the significant WAT loss commonly associated with end-of-life traits, which should have a normal body weight but preserved muscle mass.
衰弱状态是一种临床生物学综合征，影响老年人群，使其功能依赖风险更高。动物模型可为研究这一复杂情况提供工具。在本研究中，根据动物福利规定，我们分析了16月龄小鼠（C57BL/6J）与年龄匹配的正常衰老对照小鼠相比，终点状态的身体和行为特征。添加了一组6月龄小鼠以控制年龄偏差。首先，我们确定与竖毛相关的“结构性脊柱后凸”（运动中可见且不可改变的变形）是身体衰弱表型的特征，而正常衰老的老年小鼠的“姿势性脊柱后凸”（为抵消内脏体积增加而进行的调整，但在运动中减弱）则不是。两组老年小鼠均出现脱毛（拔毛）现象。在新物体恐惧的角落试验中探索活动水平正常，腓肠肌重量正常，但站立潜伏期增加表明情绪表型最差，结构性脊柱后凸可能起了作用。肝肿大和脾肿大的存在抵消了通常与生命末期特征相关的显著白色脂肪组织损失，这些小鼠体重应正常但肌肉质量得以保留。
