Anti-aging effect and gene expression profiling of dung beetle glycosaminoglycan in aged rats

BACKGROUND: This study aimed to evaluate the anti-aging effect of a newly prepared insect-derived compound, dung beetle glycosaminoglycan (GAG), given intraperitoneally to old SD rats as part of their diet for 1 month. Insect GAG administration was found to be related to a reduction in oxidative damage, hepato-cellular biomarker levels, protein carbonyl content, and malondialdehyde concentration. The anti-aging-related molecular genetic mechanisms of dung beetle GAG are not yet fully elucidated. RESULTS: Catharsius molossus (a type of dung beetle) GAG (CaG) possessed anti-aging activities; it reduced the serum level of creatinine kinase, had aortic vasorelaxant activities and cardioprotective actions, and maintained a normal glucose level in treated rats. Microarray analysis was performed with a rat 30 K cDNA clone set array to identify the gene-expression profiles of 14-month-old SD rats treated with dung beetle glycosaminoglycan 5 mg/kg (CaG5) over a 1-month period, which was done to investigate its anti-aging effect as compared to that of either Bombus ignitus (a type of bumblebee) queen GAG 5 mg/kg (IQG5) or chondroitin sulfate 10 mg/kg. CaG5 and IQG5 had marked anti-inflammatory effects, bringing about inhibition of free fatty acid, uric acid, sGPT, IL-1 beta, and CK values. In addition, anticoagulant and antithrombotic effects were seen: the concentration of factor 1 (fibrinogen) was increased in CaG- treated rat plasma. The CaG5-treated rat group, compared to the control, displayed upregulation of 131 genes, including lipocalin 2 (Lbp) and a serine peptidase inhibitor, Kaszal type3 (Spink3), and 64 downregulated genes, including lysyl oxidase (Lox), serine dehydratase (sds), and retinol saturase (Retsat). CONCLUSION: Our data suggest that dung beetle glycosaminoglycan may be a helpful treatment for aged rats, which indicates its potential as a therapeutic biomaterial for aging.