Tanshinone IIA attenuates cognitive impairment in vascular dementia rats by modulating copper homeostasis via the SLC31A1/FDX1 axis

Background Tanshinone IIA (TSA) is the core liposoluble active component of Salvia miltiorrhiza , a traditional Chinese medicine, and exhibits multiple pharmacological activities including anti-inflammation, anti-oxidation, anti-apoptosis and mitochondrial function improvement. Studies have confirmed that TSA can ameliorate cognitive function in rats with vascular dementia (VaD) by alleviating cerebral ischemic injury, inhibiting neuroinflammation, protecting the blood-brain barrier and other pathways. However, it has not been reported whether TSA exerts its neuroprotective effect by regulating the cuproptosis pathway. Focusing on cuproptosis, this study investigated the effects of TSA on cognitive impairment, neuronal injury and cuproptosis-related mechanisms in a rat model of VaD. Methods A rat model of VaD was established by permanent bilateral common carotid artery ligation (2-VO), and the model rats were treated with TSA. The cognitive impairment of VaD rats was evaluated by the Morris water maze test. Hematoxylin-eosin (HE) staining and Nissl staining were used to detect neuronal injury and loss in the hippocampus of VaD rats. Transmission electron microscopy (TEM) was performed to observe the ultrastructure of mitochondria in the hippocampus; Western blot (WB) assay was adopted to detect the expression levels of cuproptosis-related proteins, including solute carrier family 31 member 1 (SLC31A1), ferredoxin 1 (FDX1), lipoic acid synthetase (LIAS) and dihydrolipoamide transacetylase (DLAT).In vitro, an oxygen-glucose deprivation/reoxygenation (OGD/R) model was established in HT-22 cells to evaluate the effects of TSA on cell viability (CCK-8), intracellular reactive oxygen species (ROS) levels, and copper accumulation (Coppersensor-1 staining), further validating the involvement of copper homeostasis in TSA-mediated neuroprotection. Results The results revealed that TSA markedly alleviated cognitive dysfunction and neuronal damage in VaD rats. It also reversed the cuproptosis-related abnormal changes in the brain of VaD rats, and modulated the expression of SLC31A1/FDX1 pathway proteins. In vitro, TSA protected HT-22 cells from OGD/R-induced injury by reducing oxidative stress and copper accumulation.These changes were associated with amelioration of copper overload and mitochondrial damage, suggesting that TSA may exert neuroprotection partially through the regulation of cuproptosis-related pathways. Conclusion TSA effectively alleviated cognitive impairment and neuronal injury in VaD rats, and exerted neuroprotective effects both in vivo and in vitro by attenuating copper-dependent cytotoxic stress, preserving mitochondrial integrity, and modulating the SLC31A1/FDX1 axis. This study provides a new perspective and theoretical basis for the future development of targeted drugs for VaD.