Background Exposure to diisononyl phthalate (DINP), an endocrine disruptor associated with metabolic diseases and widely used in plastic products, has been linked to the development of several adverse health outcomes in the liver, including non-alcoholic fatty liver disease (NAFLD). Objective To investigate the effects and the possible molecular mechanisms of DINP exposure on lipid metabolism in human hepatocellular carcinoma cells (HepG2 cells). Methods First, HepG2 cells were treated with DINP at three time spots (24, 48, and 72 h) and eleven doses (0, 0.003, 0.01, 0.03, 0.1, 0.3, 1, 3, 10, 30, and 100 mmol·L⁻¹). Cell viability were detected using cell counting kit 8 (CCK8). Intracellular lipid deposition was determined by oil red O staining and lipid content detection, and triglyceride (TG) and cholesterol (TC) were further detected. Finally, the mRNA expression levels were detected by fluorescence quantitative PCR, including fatty acid synthesis related genes [acetyl-CoA carboxylase alpha (Accα), fatty acid synthase (Fasn), malonyl-CoA decarboxylase (Mlycd), and sterol regulatory element binding protein 1 (Srebp1)] and β-oxidation related genes [peroxisome proliferator activated receptor alpha (Pparα), AMP-activated protein kinase (Ampk), carnitine palmitoyltransferase 1A (Cpt-1a), transcription factor A, mitochondrial (Tfam), nuclear respiratory factor 1 (Nrf1), and peroxisome proliferator-activated receptor gamma and coactivator 1 alpha (Pgc1-α)]. Results Compared with the control group (0 mmol·L⁻¹), the no observed adverse effect levels (NOAEL) of HepG2 cell viability were 0.3, 0.1, and 0.1 mmol·L⁻¹ after 24, 48, and 72 h exposure to DINP, respectively, and the corresponding lowest observed adverse effect levels (LOAEL) were 1, 0.3, and 0.3 mmol·L⁻¹, respectively (P<0.05). After exposure to 30 mmol·L⁻¹ and 100 mmol·L⁻¹ DINP for 24 h, the intracellular lipid content, lipid deposition, TG, and TC levels were increased significantly compared with the control group (P<0.01). Compared with the control group, the mRNA expression levels of genes related to fatty acid synthesis, such as Mlycd, Srebp1, Fasn, and Accα, were down-regulated after the 100 mmol·L⁻¹ DINP exposure for 24 h, while the mRNA expression level of Mlycd was up-regulated in the 30 mmol·L⁻¹ group. The β-oxidation related genes such as Ampk, Pparα, and Tfam were up-regulated significantly after the 100 mmol·L⁻¹ DINP exposure, while Cpt-1a mRNA expression level was down-regulated (P<0.05). Conclusion Exposure to DINP at 30 mmol·L⁻¹ and 100 mmol·L⁻¹ can interfere with fatty acid synthesis and β-oxidation in lipid metabolism of HepG2 cells, resulting in lipid deposition.

Objective: To examine mental health problems among adolescents in Taiyuan City and its relationship to chronotype, so as to give a scientific basis for supporting mental health of middle school students. Methods: From October to November 2021, a total of 2 621 pupils were enrolled from three junior high schools and two senior high schools in Taiyuan by using a multi stage stratified cluster random sampling method to investigate demographic characteristics, mental health status, and chronotype. Chi squared test, Spearman correlation analysis and Logistic regression were used to analyze the relationship between sleep patterns and mental health problems in middle school students. Results: The proportion of morning, intermediate and evening types of middle school students sleep were 17.9%, 65.6%, and 16.4%, respectively. The overall detection rate of mental health problems was 13.8 %, which was statistically significant among middle school students in different grades, self perceived family economic status, the number of friends and sleep patterns ( χ 2=42.69, 29.15, 46.02, 93.99, P <0.05). After adjusting for grade, self perceived family economic status and the number of friends, Logistic regression analysis revealed that mental health problems were positively associated with evening type ( OR =2.84) and negatively associated with morning type ( OR =0.61)( P ＜0.05). Conclusion Chronotype is associated with mental health problems among middle school students, with a higher risk for evening type and a lower risk for morning type. Mental health of middle school students can be enhanced by changing their chronotype.