Sodium nitrite reduces lipid accumulation in steatotic cells by enhancing autophagy / 药学学报

ABSTRACT

Recent data have revealed that inhibiting autophagy exacerbates lipid accumulation in hepatocytes and nitrite treatment reduces total triglyceride levels in the high-fat diet mice. Therefore, the present study aimed to determine the effects of nitrite on simple hepatic steatosis and the possible role of autophagy. Firstly, steatotic L-02 cells were induced by incubating L-02 cells with 1.2 mmol · L(-1) oleic acid (OA) for 24 h. Secondly, steatotic L-02 cells were treated with 0.2 mmol · L(-1) sodium nitrite (SN) plus 3-methyladenine (3-MA), or chloroquine (CQ) for 24 h, and then lipid accumulation was measured with oil red O staining and triglyceride quantification. The notable steatosis could be observed in L-02 cells following exposure to 1.2 mmol · L(-1) OA for 24 h. Treatment with 0.2 mmol · L(-1) sodium nitrite reduced lipid accumulation in steatotic L-02 cells. 3-MA weakened the ability of sodium nitrite to ameliorate hepatic steatosis. Additionally, the sodium nitrite increased number of LC3-II immunostaining puncta and LC3-II protein expression was confirmed by immunofluorescence or Western blot analysis, and the effects were enhanced by CQ treatment. The number of increased cytoplasm vacuoles and lysosomes increased was confirmed by phase contrast and fluorescence microscope respectively. The increased autolysosome was detected by electron microscopy, this phenomenon could be reversed by CQ treatment. These data demonstrated that sodium nitrite enhanced the autophagic flux and decomposition of triglycerides in steatotic L-02 cells.