SiO 2 Induces Iron Overload and Ferroptosis in Cardiomyocytes in a Silicosis Mouse Model.

Objective: The aim of this study was to explore the role and mechanism of ferroptosis in SiO 2-induced cardiac injury using a mouse model. Methods: Male C57BL/6 mice were intratracheally instilled with SiO 2 to create a silicosis model. Ferrostatin-1 (Fer-1) and deferoxamine (DFO) were used to suppress ferroptosis. Serum biomarkers, oxidative stress markers, histopathology, iron content, and the expression of ferroptosis-related proteins were assessed. Results: SiO 2 altered serum cardiac injury biomarkers, oxidative stress, iron accumulation, and ferroptosis markers in myocardial tissue. Fer-1 and DFO reduced lipid peroxidation and iron overload, and alleviated SiO 2-induced mitochondrial damage and myocardial injury. SiO 2 inhibited Nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant genes, while Fer-1 more potently reactivated Nrf2 compared to DFO. Conclusion: Iron overload-induced ferroptosis contributes to SiO 2-induced cardiac injury. Targeting ferroptosis by reducing iron accumulation or inhibiting lipid peroxidation protects against SiO 2 cardiotoxicity, potentially via modulation of the Nrf2 pathway.

[Expression of HDAC9 in different brain regions in mice with cerebral ischemic stroke].

OBJECTIVE: To investigate the expression and the subcellular localization of HDAC9 in different brain regions of mice after cerebral ischemic injury and explore the association between HDAC9 and ischemic stroke. METHODS: Twenty-one male C57BL/6 mice were randomly divided into sham-operated group (n=9) and operated group (n=12). In the latter group, the mice with Zea-Longa neurological deficit scores of 2 or 3 following middle cerebral artery occlusion (MCAO) were assigned into MCAO group (n=9). Immunofluorescence was performed to investigate the subcellular localization of HDAC9 in the brain tissues on day 3 after MCAO. Western blotting and qRT-PCR were used to analyze the expression of HDAC9 in different regions of the brain. Results Immunofluorescence showed more intense HDAC9 expressions in the brain tissues around the infarct focus, and in the cells surrounding the infarct, HDAC9 expression was obviously increased in the cytoplasm and reduced in the cell nuclei. Compared with the other brain regions, the ipsilesional cortex with MCAO showed more abundant HDAC9 expressions at both the mRNA and protein levels (P<0.05). CONCLUSION: HDAC9 may be closely related to cerebral ischemic injury and participate in the pathophysiological process of ischemic stroke.