Abstract: Objective To study the apoptosis and mechanism of nicotine(Nic) in H9C2 cells under high glucose and high fat(HGHL) conditions. Methods H9C2 cells were cultured with different concentrations of nicotine (6×10^-8 mol/L Nic, 6×10^-7 mol/L Nic, 6×10^-6 mol/L Nic) for 2 hours, and HGHL (33 mmol/L glucose and 500 μmol/L palmitate) was added for 24 hours, cell proliferation was detected by CCK8 assag, cell viability was measured by lactate dehydrogenase (LDH) kit.The expression of Bax, Bcl-2, cleaved-caspase3 and caspase3 and the phosphorylation levels of ERK1/2, JNK and p38MAPK were detected by Western blot. The supernatant ROS level was determined by flow cytometry. Results Compared with normal controls, high glucose, high fat and nicotine combined with high glucose and high fat significantly inhibited cell viability and increased LDH level in the supernatant(P＜0.001). The apoptosis rate of HGHL and Nic+HGHL cells was significantly increased (P＜0.001), and the expression of cleaved-caspase3 protein was significantly increased (P＜0.01). The expression of Bcl-2/ Bax protein was significantly decreased (P＜0.01). ROS level was most significantly expressed in the Nic+HGHL group (P＜0.001). At the same time, HGHL activated MAPK phosphorylation level. ERK1/2 phosphorylation level was significantly increased in Nic+HGHL group (P＜0.01). ROS scavenger (NAC) significantly reduced caspase3 protein expression (P＜0.001). Conclusions Nicotine, high glucose and high fat can cause H9C2 cell damage and increase apoptosis, which is closely related to the regulation of ROS and MAPK signaling pathway.

Key words: nicotine, high glucose/high fat, apoptosis, MAPK