Title:Anti-TLR4 IgG2 Prevents Acetaminophen-induced Acute Liver
Injury through the Toll-like Receptor 4/MAPKs Signaling Pathway
in Mice
Volume: 23
Issue: 5
Author(s): Chuanxia Yao, Yiwen Wang, DanDan Gong, Tian Feng, Yaqiong Zhang, Chunhui Wang, Maorong Wang*Jin Zhu*
Affiliation:
- Department of Liver Disease, Jingling Hospital, Nanjing 210002, China
- Centre for Diseases Prevention and
Control of Eastern Theater, Nanjing 210002, China
Keywords:
anti-TLR4 IgG2, acetaminophen, hepatotoxicity, anti-oxidation, anti-apoptosis, anti-inflammation, TLR4/MAPKs.
Abstract:
Background and Objective: Acetaminophen (APAP) is a widely used antipyretic and
analgesic. If taken in excess, it can cause severe drug-induced acute liver injury. The purpose of
this study was to investigate the effects of anti-TLR4 IgG2 on APAP-induced liver injury and its
underlying mechanisms.
Methods: We injected APAP into the abdominal cavity of mice to establish a liver injury model.
Mice were divided into the control group, APAP group, and APAP + anti-TLR4 IgG2 group. In order
to verify the implication of the toll-like receptor4 and mitogen-activated protein kinases activation
(TLR4/MAPKs) signaling pathway, mice were intraperitoneally injected with a TLR4 / MAPKs
inhibitor anti-TLR4 IgG2. We evaluated the effects of TLR4 IgG2 on the antioxidant, anti-apoptotic,
anti-inflammatory, and liver histopathology of APAP mice. In addition, the expression of the TLR4 /
MAPKs signaling pathway was detected by Western blot.
Results: Our study showed that APAP mouse models were successfully established; however,
pretreatment with anti-TLR4 IgG2 alleviated APAP-induced hepatic injury, as evidenced by the 24-h
survival rate. Meanwhile, anti-TLR4 IgG2 prevented the elevation of serum biochemical parameters
and lipid profile. Furthermore, compared with the APAP group, hepatic antioxidants, including 3-
Nitrotyrosine, high mobility group protein B1, superoxide dismutase, catalase, and glutathione, were
increased in APAP + anti-TLR4 IgG2 group. In contrast, a significant decrease was observed in the
levels of the malondialdehyde, which is a lipid peroxidation product. Moreover, the western blotting
analysis showed that anti-TLR4 IgG2 treatment inhibited the activation of the apoptotic pathway by
increasing Bcl-2 and decreasing Bax, P53, and cleaving caspase-3 / caspase-3 protein expression.
These results were further validated by TUNEL staining and immunohistochemical.
Histopathological observation also revealed that pretreat-ment with anti-TLR4 IgG2 could
significantly reverse hepatocyte inflammatory infiltration, congestion, and necrosis in liver tissues by
APAP. Importantly, anti-TLR4 IgG2 effectively alleviated APAP-induced liver injury by inhibiting tolllike
receptor4 and mitogen-activated protein kinases activation signaling pathways (TLR4/MAPKs).
Conclusion: The results clearly suggest that the underlying molecular mechanisms in the
hepatoprotection of anti-TLR4 IgG2 in APAP-induced hepatotoxicity may be due to its antioxidation,
anti-apoptosis, and anti-inflammation effects through inhibition of the TLR4/MAPKs
signaling axis.
