Cistanche deserticola improves ovariectomized-induced osteoporosis mainly by regulating lipid metabolism: Insights from serum metabolomics using UPLC/Q-TOF-MS

Cistanche deserticola (C. deserticola) is an edible and traditional medicine widely used in China, which has been confirmed to be effective in the treatment of postmenopausal osteoporosis (PMOP). Despite its proven efficacy, the exact role of C. deserticola in bone metabolism and its underlying mechanism has remained unclear. In this research, we employed an in vivo model utilizing ovariectomized (OVX) rats to characterize the anti-osteoporotic activity and metabolic mechanism of the ethanol extract of C. deserticola (CHE). Fifty female Sprague-Dawley (SD) rats were randomly divided into five groups including sham operation group, model group, 0.1 g/kg estradiol valerate (EV) group as the positive control, low (0.6 g/kg) and high (1.2 g/kg) dosage CHE groups. Biochemical parameter analyses and histopathological experiments were conducted to assess the pharmacodynamic effects. Metabolomic analysis was conducted on serum samples to examine the metabolic profiles, identify potential biomarkers, and elucidate the metabolic pathways associated with CHE in OVX rats. CHE treatment demonstrated significant anti-osteoporosis activity by regulating serum biochemical markers of bone turnover, improving cancellous bone structure, and reversing the decrease in bone mineral density. Furthermore, the clinical equivalent dose group (CHL) achieved superior overall outcomes. The main interventions of CHE on OVX rats involved the modulation of several key pathways, including steroid hormone biosynthesis, arachidonic acid metabolism, tyrosine and tryptophan metabolism, biotin metabolism, regulation of TRP channels by inflammatory mediators, primary bile acid biosynthesis, regulation of lipolysis in adipocytes, and bile secretion. 23 potential efficacy-related biomarkers within the metabolic network were identified. Among them, long-chain unsaturated fatty acids (eg. DHA and docosapentaenoic acid), steroid hormones, amino acids and carbohydrates were strongly correlated with bone resorption and formation markers. Additionally, it was observed four pathways (nucleotide, carbon, amino acid, and lipid metabolism) were implicated in the effects of CHE. This study demonstrates that CHE improves bone loss in PMOP mainly through regulating lipid metabolism pathways, which provides an evidence base for CHE treatment of PMOP.