Hepatoprotective effects of norgalanthamine on carbon tetrachloride induced-hepatotoxicity in mice

Comparative role of acetaminophen, carbon tetrachloride and thioacetamide in development of fibrosis in rats

Background

Several hepatotoxicants such as acetaminophen, carbon tetrachloride, and thioacetamide are repeatedly used to develop hepatic fibrosis to mimic the histological and hemodynamic characteristics of human illness. It may be a good idea to establish a better model among these hepatotoxicants to develop hepatic fibrosis.

Aim

The present study evaluated comparative toxic effects of three model hepatotoxicants for experimental progression of fibrosis or cirrhosis.

Materials and methods

Acetaminophen (200 mg/kg), carbon tetrachloride (200 µl/kg) and thioacetamide (200 mg/kg) were administered orally, thrice in a week for 8 weeks in different groups. After 8 weeks of exposure, animals were euthanized, blood and tissues were collected for various hematological, serological, tissue biochemical analysis and histological observations for comparative assessment of toxic consequences.

Results

Significant deviation was noted in liver function tests, lipid peroxidation, glutathione, activities of superoxide dismutase, catalase, and GSH cycle enzymes; aniline hydroxylase, amidopyrine-N-demethylase, DNA fragmentation and level of hydroxyproline when compared with control group. Histology also depicted damage in liver histoarchitecture with exposure to acetaminophen, carbon tetrachloride and thioacetamide. Tukey's HSD post hoc test confirmed that thioacetamide produced severe toxic effects in comparison to carbon tetrachloride and acetaminophen.

Conclusion

In conclusion, toxic effects were noted in ascending order as acetaminophen.

Activated Natural Killer Cell Inoculation Alleviates Fibrotic Liver Pathology in a Carbon Tetrachloride-Induced Liver Cirrhosis Mouse Model

Activated hepatic stellate cells (HSCs) play a detrimental role in liver fibrosis progression. Natural killer (NK) cells are known to selectively recognize abnormal or transformed cells via their receptor activation and induce target cell apoptosis and, therefore, can be used as a potential therapeutic strategy for liver cirrhosis. In this study, we examined the therapeutic effects of NK cells in the carbon tetrachloride (CCl₄)-induced liver cirrhosis mouse model. NK cells were isolated from the mouse spleen and expanded in the cytokine-stimulated culture medium. Natural killer group 2, member D (NKG2D)-positive NK cells were significantly increased after a week of expansion in culture. The intravenous injection of NK cells significantly alleviated liver cirrhosis by reducing collagen deposition, HSC marker activation, and macrophage infiltration. For in vivo imaging, NK cells were isolated from codon-optimized luciferase-expressing transgenic mice. Luciferase-expressing NK cells were expanded, activated and administrated to the mouse model to track them. Bioluminescence images showed increased accumulation of the intravenously inoculated NK cells in the cirrhotic liver of the recipient mouse. In addition, we conducted QuantSeq 3' mRNA sequencing-based transcriptomic analysis. From the transcriptomic analysis, 33 downregulated genes in the extracellular matrix (ECM) and 41 downregulated genes involved in the inflammatory response were observed in the NK cell-treated cirrhotic liver tissues from the 1532 differentially expressed genes (DEGs). This result indicated that the repetitive administration of NK cells alleviated the pathology of liver fibrosis in the CCl₄-induced liver cirrhosis mouse model via anti-fibrotic and anti-inflammatory mechanisms. Taken together, our research demonstrated that NK cells could have therapeutic effects in a CCl₄-induced liver cirrhosis mouse model. In particular, it was elucidated that extracellular matrix genes and inflammatory response genes, which were mainly affected after NK cell treatment, could be potential targets.

Combined Silymarin and Cotrimoxazole Therapy Attenuates Pulmonary Fibrosis in Experimental Paracoccidioidomycosis

Paracoccidioidomycosis (PCM), which mainly affects rural workers, is a systemic mycosis caused by the Paracoccidioides genus that induces pulmonary sequelae in most adult patients, causing serious disability and impairing their quality of life. Silymarin is herbal medicine with an effective antifibrotic activity. Considering that in PCM, antifibrotic treatment is still not available in pulmonary fibrosis, we aimed to evaluate combined silymarin and cotrimoxazole (CMX) therapy via the intratracheal route in BALB/c mice infected with P. brasiliensis yeast. After 12 weeks of treatment, the lungs were collected for the determination of fungal burden, production of OH-proline, deposition of collagen fibers, pulmonary concentrations of cytokines, and expression of fibronectin, α-SMA, MMP-2, MMP-9, and TIMP-2. Spleen cell cultures were also performed. Our results showed that infected mice treated with combined silymarin/CMX showed lower deposition of collagen fibers in the lungs and lower pulmonary concentrations of hydroxyproline than the placebo groups. Decreased levels of TGF-β1 and fibronectin and high levels of MMP-2 and IFN-γ were also observed in this group of mice. Collectively, our findings indicate that the combination of antifungal treatment with silymarin has a potent antifibrotic effect associated with an immunomodulatory effect that potentializes the antifungal immune response.