Catalpol alleviates hypoxia ischemia-induced brain damage by inhibiting ferroptosis through the PI3K/NRF2/system Xc-/GPX4 axis in neonatal rats.

Hypoxic-ischemic encephalopathy (HIE) is a brain damage caused by perinatal hypoxia and blood flow reduction. Severe HIE leads to death. Available treatments remain limited. Oxidative stress and nerve damage are major factors in brain injury caused by HIE. Catalpol, an iridoid glucoside found in the root of Rehmannia glutinosa, has antioxidant and neuroprotective effects. This study examined the neuroprotective effects of catalpol using a neonatal rat HIE model and found that catalpol might protect the brain through inhibiting neuronal ferroptosis and ameliorating oxidative stress. Behavior tests suggested that catalpol treatment improved functions of motor, learning, and memory abilities after hypoxic-ischemic injury. Catalpol treatment inhibited changes to several ferroptosis-related proteins, including p-PI3K, p-AKT, NRF2, GPX4, SLC7A11, SLC3A2, GCLC, and GSS in HIE neonatal rats. Catalpol also prevented changes to several ferroptosis-related proteins in PC12 cells after oxygen-glucose deprivation. The ferroptosis inducer erastin reversed the protective effects of catalpol both in vitro and in vivo. We concluded that catalpol protects against hypoxic-ischemic brain damage (HIBD) by inhibiting ferroptosis through the PI3K/NRF2/system Xc-/GPX4 axis.

Investigation of calcium variations in single cells and the impact of Yoda1 on osteocytes by ICP-OES.

BACKGROUND: Detection of elements in individual cells by inductively coupled plasma (ICP) spectrometry has recently attracted significant interest in biological research, due to the unique ability of ICP spectrometry for trace element analysis. However, performing single-cell analysis using ICP optical emission spectrometry (ICP-OES) remains a challenge due to the small size and discrete nature of cells. This is while ICP-OES can serve as a cost-effective and label-free method for this purpose. Therefore, it is necessary to improve the current ICP-OES technique to facilitate the detection of elements in single cells, thereby unlocking novel applications. RESULTS: A new conical ICP torch, which has been illustrated to offer better analytical performance than the conventional ones, was applied to achieve the detection of calcium in single micro-sized cells. A new heated chamber was designed and coupled with a high-efficiency nebulizer as the sample introduction system. For the detection of single SiO2 particles, the number of particle events obtained by the new sample introduction system was found to be up to 9 times higher than that of the conventional system without sacrificing the signal intensity. Subsequently, calcium in human breast cancer cells (MDA-MB-231), mice breast cancer cells (Py8119), and mice osteocytes (MLO-Y4) was successfully detected using the new ICP-OES system. The cell detection efficiency turned out to be around 2%-3% which is much higher than that the reported values in previous single-cell ICP-OES research. Finally, as a new application, the effect of Yoda1, a recently identified activator of Piezo1 calcium channel, on osteocytes was investigated. The calcium content in Yoda1-treated MLO-Y4 cells was seen increase by 36% compared to the control sample. SIGNIFICANCE: This research reveals the capability of ICP-OES in single-cell analysis for micro-sized cells which was made possible by the new conical ICP torch and the new sample introduction system. The ability to detect calcium in single mammalian cells enables the first ever application of this technique to assess the impact of the Yoda1 activator on the calcium level in osteocytes.