Validation of a mouse model of frailty in aged male C57BL/6J mice constructed through Frailty Index-31 Scoring System

WANG Yanan; WANG Hong; ZHENG Shujuan; LI Yu; OUYANG Juyan; TIAN Tian; MIYESAI Ainiwaer

doi:10.3969/j.issn.1009-0126.2025.12.026

Abstract：Objective To assess the frailty index(FI)of aged male C57BL/6J mice using the FI-31 scoring system,and to validate the effectiveness of the frailty model by integrating pathological examination and serum biomarker detection.Methods Five 6-month-old mice in the experimental animal center of our university were subjected and served as a young group.Another 10 14-month-old male C57BL/6J mice(SPF grade)were divided into a senescence group and a frailty group according to the FI-31 value,with 5 mice in each group.The FI value was compared among the three groups.The heart,liver,kidneys,spleens,and gastrocnemius muscle were collected from the three groups for pathological staining and observation,and serum senescence-associated secretory phenotype biomarkers were measured using ELISA.Results The FI-31 score was significantly higher in the senescence group and the frailty group than the young group(P＜0.05).The frailty group exhibited progressively frail in varying organs,showing segmental arterial intimal necrosis in the heart,aggravative steatosis in the liver,mesangial cell proliferation in the kidneys,macrophage deposition in the spleen,and muscle atrophy.Elevated serum levels of IL-6,IL-1β,TNF-α,MCP-1,and CXCL-10,and decreased G6PD level were observed in the frailty group when compared with the young group and the senescence group(P＜0.05).The pathological scores of the heart,liver,kidneys and spleen were 0.2-0.4 in the young group,1.4-1.8 in the senescence group and 1.6-2.2 in the frailty group.Conclusion The combination of FI-31 scoring,pathological examination,and serum biomarker detection provides a reference for assessing tissue and serum changes in frail mice.