The Late-Stage Protective Effect of Mito-TEMPO against Acetaminophen-Induced Hepatotoxicity in Mouse and Three-Dimensional Cell Culture Models.

Mohammad Abdullah-Al-Shoeb,Nanami Namba,Hitoshi Maeda,Kenta Sasaki,Saori Kikutani,Yoichi Ishitsuka,Toru Maruyama,Tetsumi Irie,Yuki Kondo,Keiichi Ueno

doi:10.3390/antiox9100965

Abstract

An overdose of acetaminophen (APAP), the most common cause of acute liver injury, induces oxidative stress that subsequently causes mitochondrial impairment and hepatic necroptosis. N-acetyl-L-cysteine (NAC), the only recognized drug against APAP hepatotoxicity, is less effective the later it is administered. This study evaluated the protective effect of mitochondria-specific Mito-TEMPO (Mito-T) on APAP-induced acute liver injury in C57BL/6J male mice, and a three dimensional (3D)-cell culture model containing the human hepatoblastoma cell line HepG2. The administration of Mito-T (20 mg/kg, i.p.) 1 h after APAP (400 mg/kg, i.p.) injection markedly attenuated the APAP-induced elevated serum transaminase activity and hepatic necrosis. However, Mito-T treatment did not affect key factors in the development of APAP liver injury including the activation of c-jun N-terminal kinases (JNK), and expression of the transcription factor C/EBP homologous protein (CHOP) in the liver. However, Mito-T significantly reduced the APAP-induced increase in the hepatic oxidative stress marker, nitrotyrosine, and DNA fragmentation. Mito-T markedly attenuated cytotoxicity induced by APAP in the HepG2 3D-cell culture model. Moreover, liver regeneration after APAP hepatotoxicity was not affected by Mito-T, demonstrated by no changes in proliferating cell nuclear antigen formation. Therefore, Mito-T was hepatoprotective at the late-stage of APAP overdose in mice.

Highlights

Acetaminophen (N-acetyl-p-amino phenol; Paracetamol; APAP) is an over-the-counter drug, mostly used as an analgesic and antipyretic for different age groups worldwide with some after-effectsAntioxidants 2020, 9, 965; doi:10.3390/antiox9100965 www.mdpi.com/journal/antioxidantsAntioxidants 2020, 9, 965 at therapeutic doses [1,2]
The purpose of this study was to confirm the effectiveness of Mito-T against acute liver injury induced by an overdose of APAP, and the protective effect of Mito-T against APAP-induced mitochondrial oxidative stress, nitrotyrosine formation, and hepatic necroptosis in mice
We found that 5–20 mg/kg Mito-T significantly (p < 0.01) suppressed the APAP-induced increase in serum ALT levels whereas 2 mg/kg of Mito-T had no protective effect (Figure 1A)

Summary

Introduction

Acetaminophen (N-acetyl-p-amino phenol; Paracetamol; APAP) is an over-the-counter drug, mostly used as an analgesic and antipyretic for different age groups worldwide with some after-effectsAntioxidants 2020, 9, 965; doi:10.3390/antiox9100965 www.mdpi.com/journal/antioxidantsAntioxidants 2020, 9, 965 at therapeutic doses [1,2]. An accidental or intentional overdose of APAP can cause acute hepatotoxicity that progresses to acute liver failure (ALF) [3]. N-acetyl-p-benzoquinoneimine (NAPQI), a glutathione (GSH) conjugate [8,9]. Following an overdose of APAP, hepatic GSH becomes depleted and the NAPQI concentration increases. The excessively unstable toxic metabolite NAPQI can bind to sulfhydryl groups of cellular and mitochondrial proteins (for example, glutathione peroxidases, ATP synthase α-subunit) [10,11]. The progression of hepatic injury involves multiple mediators including ROS, activated c-jun N-terminal kinase (JNK), C/EBP homologous protein (CHOP) induction, peroxynitrite, nitrotyrosine formation, and inflammatory mediators including interleukins (IL) and TNF-α [15,17,18,19,20,21,22]

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