Background  Long-term alcohol consumption can cause serious liver damage. As a new programmed cell death mode, necroptosis is involved in the pathogenesis of alcoholic liver disease (ALD). Mitochondrial unfolded protein response (UPR^mt) can promote cell recovery and improve mitochondrial network survival. Exploring the role of UPR^mt in ALD may provide a new potential target for clinical practice.

  Objective  To investigate the effect of UPR^mt on mitochondrial function and ethanol-induced hepatocyte necroptosis and supplement mechanisms of UPR^mt in hepatocyte mitochondrial network.

  Methods  Four groups were constructed, including normal control group (NC), alcoholic liver disease group (ALD), UPR^mt activation control group (NC + Omy), and UPR^mt activation alcoholic liver disease group (ALD + Omy). ALD group was cultured in the completed culture medium with 250 mmol/L ethanol, and 10 μmol/L oligomycin A was added 6 hours before modeling to activate hepatocytes UPR^mt. RT-PCR was used to detect key genes transcriptional levels of UPR^mt, mitochondrial fission and necroptosis. Fluorescence probe was used to observe mitochondrial function. Western blotting was performed to detect the expression levels of mitophagy proteins, such as microtubule-associated protein 1 light chain 3 (LC3), P62 and Fundc1.

  Results  RT-PCR results showed that the transcription level of UPR^mt related genes mtDNAj, CHOP, ATF5 and inflammatory factor TNF- α, IL-6 and Timp1 increased induced by alcohol, and the expression of key genes of necrotic apoptosis RIPK3 and PGAM5 also increased (P<0.05). The mitochondrial membrane potential significantly decreased while the production of mtROS increased in ALD model (P<0.05). Western blotting results showed reduced mitophagy and abnormal mitochondrial fission in ALD model. Oligomycin A intervention reversed these damages, threfore reducing inflammation and oxidative stress, maintaining the normal mitochondrial function, and inhibiting hepatocytes necroptosis.

  Conclusion  UPR^mt alleviates alcohol-induced hepatocyte necroptosis by rescuing oxidative stress and mitochondrial dysfunction.