Oltipraz

Ferroptosis is a form of regulating cell death, and iron accumulation in the brain after acute ischemic stroke (AIS) is associated with the triggering of iron metabolism. Nuclear factor erythroid 2-related factor 2 (Nrf2), one of the most critical antioxidant transcription factors in cells, is closely associated with ferroptosis and oxidative stress.In the present study, we explore the intrinsic mechanisms by which Nrf2 exerts neuroprotective effects against AIS-induced ferroptosis.In vivo experiments, we explored the protective effects of AIS induced by middle cerebral artery occlusion (MCAO) and its mechanisms by using intraperitoneal injections of ferrostatin-1 (Fer-1, an inhibitor of ferroptosis), Oltipraz (an agonist of Nrf2) and ML385 (an inhibitor of Nrf2) in wild-type (WT) mice, as well as using Nrf2^-/- mice. In vitro experiments, we investigated the mechanism of action of Nrf2 on the establishment of a ferroptosis cell model induced by Erastin by overexpressing or silencing Nrf2 expression using shRNA in SH-SY5Y cells.Ferroptosis played an important role in AIS, and Fer-1 inhibited iron accumulation and alleviated neuronal damage caused by AIS.Oltipraz attenuated AIS-induced neuronal damage and cerebral infarction by increasing cortical blood flow (CBF). Additionally, Oltipraz protected against AIS-induced ferroptosis by reducing oxidative stress and iron overload. Meanwhile, in Oltipraz-treated AIS mice, Nrf2, solute carrier family 7 member 11 (SLC7A11/xCT), and glutathione peroxidase 4 (GPX4) were upregulated. Conversely, ML385 decreased CBF and exacerbated IS-induced neuronal damage. Furthermore, both ML385 treatment and Nrf2 knockout mice exacerbated oxidative stress injury and iron overload and downregulated the expression of both xCT and GPX4. Consistent with the in vivo results, Nrf2 conferred ferroptosis resistance in vitro upon exposure to compounds that induce ferroptosis, by modulating the xCT/GPX4 pathway.The present study confirmed that Nrf2 could attenuate AIS-induced neuronal ferroptosis and oxidative stress by regulating xCT/GPX4.

Morphine effectively relieves severe pain but leads to analgesic tolerance with long-term use.The molecular mechanisms underlying morphine tolerance remain incompletely understood. Existing literature suggests that chemokine CCL2, present in the spinal cord, plays a role in central nervous system inflammation, including neuropathic pain. Nevertheless, the precise mechanism through which CCL2 mediates morphine tolerance has yet to be elucidated. Consequently, this study aims to investigate the molecular pathways by which CCL2 contributes to the development of morphine analgesic tolerance.

Rats were administered intrathecal morphine (10 μg/5 μl) twice a day for seven consecutive days to induce a model of morphine nociceptive tolerance. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression levels of CCL2 and its related mechanism molecules. Immunofluorescence was used to detect the localization of CCL2 in the spinal cord. Intrathecal injections of inhibitors or agonists to artificially regulate the expression of relevant molecules. The thermal tail-flick experiment was performed to evaluate morphine tolerance in rats.

Morphine-induced CCL2 expression was significantly increased in spinal cord, while conversely, the expressions of Nrf2 and PGC-1a were downregulated. Immunofluorescence showed that the enhanced immune response of CCL2 mainly co-localized with neurons. In vivo, we confirmed that intrathecally injection of CCL2 inhibitor Bindarit could effectively alleviate the occurrence of apoptosis and alleviate morphine tolerance. Similarly, pretreatment with Nrf2 signaling pathway agonist Oltipraz and PGC-1α agonist ZLN005 also achieved similar results, respectively. ROS Fluorescence Assay Kit indicated that increasing the expression of PGC-1α could alleviate the occurrence of apoptosis by reducing the level of ROS.

Our data emphasize that chemokine CCL2 inhibited the Nrf2 signaling pathway and PGC-1α-mediated mitochondrial biogenesis, alleviating the occurrence of apoptosis in spinal cord, thereby participating in morphine tolerance. This may provide new targets for the treatment of morphine tolerance.