The MAP2K4/JNK/c-Jun Signaling Pathway Plays A Key Role In Dexmedetomidine Protection Against Acetaminophen-Induced Liver Toxicity

ERK/NF-kB/COX-2 Signaling Pathway Plays a Key Role in Curcumin Protection against Acetaminophen-Induced Liver Injury

Recent experimental studies have highlighted the beneficial effects of curcumin on liver injury induced by acetaminophen (APAP). However, the specific molecular mechanisms underlying curcumin's hepatoprotective effects against APAP-induced liver injury remain to be fully elucidated. This study aimed to investigate the therapeutic effect of curcumin on APAP-induced liver injury using a mouse model. In the experiment, mice were subjected to an intraperitoneal hepatotoxic dose of APAP (300 mg/kg) to induce hepatotoxicity. After 30 min of APAP administration, the mice were treated with different concentrations of curcumin (0, 10, 25, or 50 mg/kg). After 16 h, mice with hepatotoxicity showed elevated levels of serum alanine transaminase (ALT), aspartate transaminase (AST), hepatic myeloperoxidase (MPO), TNF-α, and IL-6, and decreased levels of glutathione (GSH). Moreover, there was an increased infiltration of neutrophils and macrophages following intraperitoneal injection of APAP. However, curcumin-treated mice displayed a pronounced reduction in serum ALT, AST, hepatic MPO, TNF-α, and IL-6 levels, coupled with a notable elevation in GSH levels compared to the APAP-treated hepatotoxic mice. Moreover, curcumin treatment led to reduced infiltration of neutrophils and macrophages. Additionally, curcumin inhibited the phosphorylation of ERK and NF-kB proteins while reducing the expression of cyclooxygenase-2 (COX-2). These findings highlight the hepatoprotective potential of curcumin against APAP-induced liver injury through the suppression of the ERK, NF-kB, and COX-2 signaling pathways.

Dexmedetomidine Mediates Neuroglobin Up-Regulation and Alleviates the Hypoxia/Reoxygenation Injury by Inhibiting Neuronal Apoptosis in Developing Rats

Background

Exploring the effective therapy for neonatal hypoxic-ischemic brain injury is an important goal. This study was designed to investigate how dexmedetomidine (DEX) contribute to hypoxic brain injury.

Methods

Developing Sprague-Dawley rat models of hypoxia/reoxygenation (H/R) injury were constructed to simulate neonatal hypoxic brain injury for DEX treatment. Immunohistochemistry and western blot were performed to measure neuroglobin (Ngb) protein expression in hippocampal tissues. Hippocampal neuron injury and apoptosis were detected by Nissl staining and TUNEL assay, respectively. A Morris water maze (MWM) test was performed to evaluate the long-term learning and memory function.

Results

The expression of Ngb was increased following H/R model establishment and up-regulated by medium and high doses of DEX, but not up-regulated by low doses of DEX. Medium and high doses of DEX alleviated the H/R injury as well as induced the reduction of Nissl bodies and apoptosis. Besides, medium and high doses of DEX down-regulated cytosolic Cyt-c, Apaf-1, and caspase-3 in H/R injury model. MWM test showed that medium and high doses of DEX significantly shortened the escape latency and enhanced the number of platform crossings. However, low doses of DEX have no effect on Nissl bodies, mitochondrial apoptosis, expression of apoptosis-related proteins and long-term learning functions.

Conclusions

DEX induced Ngb expression in H/R rat models. The neuroprotection of DEX-mediated Ngb up-regulation may be achieved by inhibiting neuronal apoptosis through the mitochondrial pathway. Findings indicated that DEX may be useful as an effective therapy for neonatal hypoxic brain injury.