Betulinic acid abates N-nitrosodimethylamine-induced changes in lipid metabolism, oxidative stress, and inflammation in the liver and kidney of Wistar rats

Olsalazine pretreatment augments chemosensitivity of gemcitabine in hepatocellular carcinoma

Recently, olsalazine a DNA hypomethylating agent was found to inhibit the growth of breast cancer cells. The present study was carried out to evaluate the effects of olsalazine pretreatment in the potentiation of chemosensitivity of gemcitabine for the treatment of hepatocellular carcinoma (HCC). In silico molecular docking was performed to analyze the interaction of olsalazine and gemcitabine with DNMT1 and DNA, respectively, using the AutoDock tools 1.5.6. Cytotoxicity of olsalazine, gemcitabine, and combination were measured on human HePG2 cells using MTT assay. Antiproliferative effects were assessed using animal model of N-nitrosodiethylamine and carbon tetrachloride-induced HCC. Treatment was initiated from 8th week of induction to 11th week and change in body weight, liver weight, and survival rate were measured. Following treatment, blood samples were collected for estimation serum biochemistry. Blood serum was used for the estimation of inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), C-reactive protein [CRP], lactate dehydrogenase (LDH), and P53 levels. Oxidative stress markers were measured in liver tissue homogenates. Histopathology and immunohistochemistry (IHC) were performed on liver sections to detect the morphological changes and P53 expression. Docking analysis revealed the interactions between olsalazine and DNMT1 with a binding energy score of -5.34 and gemcitabine and DNA with a binding energy score of -5.93. Olsalazine pretreatment potentiated the antiproliferative effect of gemcitabine in cell line study. In the group receiving olsalazine pretreatment showed significant reductions in relative liver weight and improved survival rate of gemcitabine treatment group. Serum biochemical markers: serum glutamate pyruvate transaminase, serum glutamic oxaloacetic transaminase, alkaline phosphatase, and bilirubin revealed improved liver functions. Olsalazine pretreatment also reduced the levels of inflammatory markers like CRP, LDH, TNF-α, and IL-6 and oxidative stress markers dose dependently. Histopathology and IHC showed improved liver morphology with potentiated the induction of P53 upon olsalazine pretreatment in combination with gemcitabine. In conclusion, sequential combination of olsalazine and gemcitabine improved the treatment outcomes during the progression of HCC.

Source-specific nitrate intake and all-cause mortality in the Danish Diet, Cancer, and Health Study

INTRODUCTION

Nitrate and nitrite are naturally occurring in both plant- and animal-sourced foods, are used as additives in the processing of meat, and are found in water. There is growing evidence that they exhibit a spectrum of health effects, depending on the dietary source. The aim of the study was to examine source-dependent associations between dietary intakes of nitrate/nitrite and both all-cause and cause-specific mortality.

METHODS

In 52,247 participants of the Danish Diet, Cancer and Health Study, associations between source-dependent nitrate and nitrite intakes--calculated using comprehensive food composition and national drinking water quality monitoring databases--and all-cause, cardiovascular disease (CVD)-related, and cancer-related mortality over 27 years were examined using restricted cubic splines within Cox proportional hazards models adjusting for demographic, lifestyle, and dietary confounders. Analyses were stratified by factors hypothesised to influence the formation of carcinogenic N-nitroso compounds (namely, smoking and dietary intakes of vitamin C, vitamin E, folate, and polyphenols).

RESULTS

Plant-sourced nitrate intake was inversely associated with all-cause mortality [HRQ5vsQ1: 0.83 (0.80, 0.87)] while higher risks of all-cause mortality were seen for higher intakes of naturally occurring animal-sourced nitrate [1.09 (1.04, 1.14)], additive permitted meat-sourced nitrate [1.19 (1.14, 1.25)], and tap water-sourced nitrate [1.19 (1.14, 1.25)]. Similar source-dependent associations were seen for nitrite and for CVD-related and cancer-related mortality except that naturally occurring animal-sourced nitrate and tap water-sourced nitrate were not associated with cancer-related mortality and additive permitted meat-sourced nitrate was not associated with CVD-related mortality. No clear patterns emerged in stratified analyses.

CONCLUSION

Nitrate/nitrite from plant sources are inversely associated while those from naturally occurring animal-sources, additive-permitted meat sources, and tap water-sources are positively associated with mortality.

The Effect of Heat-Killed Lactobacillus plantarum on Oxidative Stress and Liver Damage in Rats with Bile Duct Ligation-Induced Hepatic Fibrosis

This study is aimed at evaluating the effects of heat-killed Lactobacillus plantarum (L. plantarum) on cholestatic liver injury induced by bile duct ligation (BDL) in rats. Rats in the first group were healthy (normal control) and in the second group underwent abdominal incision (sham control). Rats in the third and fourth groups underwent common bile duct ligation and were treated with either oral distilled water (BDL control group) or heat-killed L. plantarum (BDL + L. plantarum) for 28 days. Finally, rats were sacrificed, blood samples were analyzed through biochemical methods, liver and ileum tissue tissues were histologically assessed, and the expression of the αSMA, TNF-α, IL-6, and IL-10 genes in the liver and ZO-1 gene in ileum tissues were assessed through real-time PCR. The levels of bilirubin, liver function enzymes, NO, MDA, and carbonyl protein in the BDL + L. plantarum group were significantly lower than in the BDL control group (P ≤ 0.05). SOD and CAT activity in BDL + L. plantarum group was significantly greater than the BDL control group 1.4 and 3.0 times, respectively (P ≤ 0.001). Moreover, in the BDL + L. plantarum group, the expression of the α-SMA, TNF-α, and IL-6 genes was significantly lower (3.1, 2.9, and 2.5 times), and IL-10 and ZO-1 genes were significantly greater than the BDL control group by 2.1 and 3.6 times, respectively (P ≤ 0.05). The histological assessment also confirmed the greater effectiveness of heat-killed L. plantarum in improving the morphology and parenchymal structure of the liver. Taken together, our results suggest that heat-killed L. plantarum strains are potential therapeutic agents for hepatic fibrosis.

Betulinic acid mitigates zearalenone-induced liver injury by ERS/MAPK/Nrf2 signaling pathways in mice

Zearalenone (ZEA) is a mycotoxin commonly found in cereals and feedstuffs, which can induce oxidative stress and inflammation to cause liver damage in humans and animals. Betulinic acid (BA) is extracted from pentacyclic triterpenoids of many natural plants and has anti-inflammatory, and anti-oxidation biological activities in many studies. However, the protective effect of BA on liver injury induced by ZEA has not been reported. Therefore, this study aims to explore the protective effect of BA on ZEA-induced liver injury and its possible mechanism. In the mice experiment, ZEA exposure increased the liver index and caused histopathological impairment, oxidative damage, hepatic inflammatory responses, and increased hepatocyte apoptosis. However, when combined with BA, it could inhibit the production of ROS, up-regulate the proteins expression of Nrf2 and HO-1 and down-regulate the expression of Keap1, and alleviate oxidative damage and inflammation in the liver of mice. In addition, BA could alleviate ZEA-induced apoptosis and liver injury in mice by inhibiting the endoplasmic reticulum stress (ERS) and MAPK signaling pathways. In conclusion, this study revealed the protective effect of BA on the hepatotoxicity of ZEA for the first time, providing a new perspective for the development of ZEA antidote and the application of BA.

Inhibition of the NF-κB pathway and ERK-mediated mitochondrial apoptotic pathway takes part in the mitigative effect of betulinic acid on inflammation and oxidative stress in cyclophosphamide-triggered renal damage of mice

Betulinic acid (BA), an occurring pentacyclic triterpenoid, has various biological activities, such as anti-inflammation and antioxidation. Previous studies found that BA attenuated cyclophosphamide (CYP)-induced intestinal mucosal damage by inhibiting intestinal mucosal barrier dysfunctions and cell apoptosis. However, the effects and regulation mechanisms of BA on CYP-induced renal damage has not been reported in literature. Here, we found that BA pretreatment alleviated the elevation of serum urea level and inhibited the increase in serum neutrophil gelatinase-associated lipocalin level induced by CYP. Meanwhile, BA ameliorated renal tubular epithelial cell edema, and vacuolization of renal cortical tubular and renal glomerulus. Moreover, pretreatment with BA inhibited the mRNA expressions of pro-inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α, and increased mRNA expressions of anti-inflammatory cytokines such as IL-10 and transforming growth factor-β by inactivation nuclear factor kappa-B. Simultaneously, BA decreased the accumulation of reactive oxygen species and malondialdehyde, and lowered the levels of superoxide dismutase and glutathione, while increased the activity of glutathione peroxidase in CYP-induced kidney damage mice. Besides, BA reduced the phosphorylation of extracellular signal-regulated kinases (ERK), inhibited the ratio of Bcl-2/Bax and cell apoptosis in CYP-triggered kidney damage. Furthermore, BA and/or PD98059 (an inhibitor of ERK) regulated mitigation of CYP-elicited renal injury and deactivation of the ERK pathway and mitochondrial apoptotic pathway, indicating that the protective effect of BA on CYP-induced renal damage may be associated with the down-regulation of ERK-mediated mitochondrial apoptotic pathway. Thus, BA could be a candidate agent against chemotherapy drug-induced nephrotoxicity by reducing inflammation and oxidative stress through suppression of ERK-mediated mitochondrial apoptotic pathway.

Lipid metabolism disorders contribute to hepatotoxicity of ICR mice induced by nitrosamines exposure

Health risks caused by crucial environmental carcinogens N-nitrosamines triggered ubiquitous attention. As the liver exerted vital function through metabolic process, lipid metabolism disorders have been confirmed as potential drivers for toxicological effects, and the mechanisms of lipid regulation related to hepatotoxicity induced by N-nitrosamines remained largely unclear. In this study, we comprehensively explored the disturbance of hepatic lipid homeostasis in mice induced by nitrosamines. The results implied that nitrosamines exposure induced hepatotoxicity accompanied by liver injury, inflammatory infiltration, and hepatic edema. Lipidomics profiling analysis indicated the decreased levels of phosphatidic acids (PA), phosphatidylcholines (PC), phosphatidylethanolamines (PE), lyso-phosphatidylcholines (LPC), lyso-phosphatidylethanolamines (LPE), diacylglycerols (DAG) and triacylglycerols (TAG), the elevation of ceramides (Cer) and decomposition of free fatty acids (FFA) in high-dose nitrosamines exposure group. Importantly, nitrosamines exposure promoted fatty acid oxidation (FAO) by facilitating fatty acid uptake and decomposition, together with the upregulation of genes associated with FAO accompanied by the activation of inflammatory cytokines TNF-α, IL-1β and NLRP3. Furthermore, fatty acid translocase CD36-mediated fatty acid oxidation was correlated with the enhancement of oxidative stress in the liver caused by nitrosamines exposure. Overall, our results contributed to the new strategies to interpret the early toxic effects of nitrosamines exposure.

Glycosylated Zein Composite Nanoparticles for Efficient Delivery of Betulinic Acid: Fabrication, Characterization, and In Vitro Release Properties

Betulinic acid (BA) has anti-inflammatory, antioxidative stress, and antitumor activities, but BA bioavailability is low due to its poor water solubility and short half-life. This study aimed to construct a BA delivery system to improve its utilization in vitro. Glycosylated zein (G-zein) was prepared using the wet heating method, and BA-loaded zein composite nanoparticles were prepared using the antisolvent method. Compared to zein, G-zein had the advantages of higher solubility and lower surface hydrophobicity. The encapsulation efficiency of G-zein@BA reached over 80% when the BA concentration was 1 mg/mL. Compared to zein@BA nanoparticles, G-zein@BA was characterized by smaller droplets, higher encapsulation efficiency, and a more stable morphology. The sustained release and solubility of G-zein@BA nanoparticles were also superior to those of zein@BA. Compared with free BA, the dispersions of zein@BA and G-zein@BA nanoparticles in water increased 2.27- and 2.91-fold, respectively. In addition, zein@BA and G-zein@BA nanoparticles markedly inhibited the proliferation of HepG2 cells. This study provides new insights into the structural properties and antitumor activity of BA composite nanoparticles to aid in the development of zein particles as functional materials to deliver bioactive compounds.

Effects of early florfenicol exposure on glutathione signaling pathway and PPAR signaling pathway in chick liver

Florfenicol (FFC) is a common antibiotic for animals. The nonstandard and excessive use of FFC can cause veterinary drug residues in animals, pollute soil and marine environment, and even threaten human health. Therefore, it is necessary to study the toxicity and side effects of FFC on animals. Our previous studies have proved that FFC can cause liver injury in chicks, but there are few in-depth studies on the mechanism of FFC causing liver injury at the level of signaling pathway in chicks. Therefore, transcriptome and proteome sequencing were performed and combined analysis was performed. Sequencing results showed that 1989 genes and 917 proteins were significantly changed in chick livers after FFC exposure. These genes and proteins are related to redox, glutathione transferase activity and lipid metabolism. There are 9 significantly different genes and 7 significantly different proteins in glutathione signaling pathway. Oxidative stress may occur in the liver of chicks through the change of activation state of glutathione signaling pathway. And there are 13 significantly different genes and 18 significantly different proteins in PPAR signaling pathway. The changes of PPAR signaling pathway may induce lipid metabolism disorder in liver. The verification results of qPCR and PRM were consistent with the sequencing results. We also detected GSH-Px, GSH, GST, TG, TC and ANDP levels in liver. These changes of biochemical indicators directly confirmed oxidative stress and lipid metabolism disorders were occurred in the livers of chicks treated by FFC. In conclusion, FFC could induce liver injury in chicks by regulating the expression levels of significantly different genes and proteins in glutathione signaling pathway and PPAR signaling pathway.

Reactive oxygen species-mediated activation of NLRP3 inflammasome associated with pyroptosis in Het-1A cells induced by the co-exposure of nitrosamines

Nitrosamines were a class of important environmental carcinogens associated with digestive tract neoplasms. As the early toxic effect of nitrosamines, inflammatory response participated in the malignant transformation of cells and promoted the occurrence and development of tumors. However, the role of NLRP3 inflammasome in the nitrosamines-induced inflammatory response was unclear. In this study, the human esophageal epithelial cells (Het-1A) were used to explore potential mechanisms of the activation of NLRP3 inflammasome under co-exposure to nine nitrosamines commonly found in drinking water at the doses of 0, 4, 20, 100, 500, and 2500 ng/mL. The results showed that nitrosamines stimulated activation of the NLRP3 inflammasome and induced cellular oxidative damage in a dose-dependent manner. Pretreatment of reactive oxygen species scavenger N-acetyl-L-cysteine (NAC), particularly mitochondrial reactive oxygen species (mtROS) scavengers Mito-TEMPO, effectively inhibited the activation of NLRP3 inflammasome, suggesting that nitrosamines could mediate the activation of NLRP3 inflammasome via mtROS. Furthermore, we found that nitrosamines co-exposure also promoted cell pyroptosis through the NLRP3/caspase-1/GSDMD pathway, which was demonstrated by adding the caspase-1 inhibitor Z-YVAD-FMK and constructing NLRP3 downregulated Het-1A cell line. This study revealed the underlying mechanism of the activation of NLRP3 inflammasome initiated by nitrosamines co-exposure and provided new perspectives on the toxic effects of nitrosamines.

Dysregulation of fatty acid metabolism associated with esophageal inflammation of ICR mice induced by nitrosamines exposure

Nitrosamines, as ubiquitous environmental carcinogens with adverse impact on human health, were crucial inducers of esophageal cancer (EC). Esophageal inflammation (EI) was an important biological process and considered to be associated with the progression of EC. However, the underlying regulatory mechanism of EI process caused by nitrosamines exposure remained largely unclear. In this study, a metabolomics approach based on mass spectrometry was utilized to explore the effect of nitrosamines exposure to ICR mice. Also, the changes of pivotal metabolic enzyme levels, urinary nitrosamines and histopathological analysis were evaluated. The results showed that nitrosamines exposure was intimately interrelated with EI process in mice. Metabolomics profiling analysis indicated that nitrosamines caused significant alterations of metabolic pathway predominantly enriched in fatty acid metabolism. Targeted metabolomics analysis revealed that nitrosamines promoted decomposition of fatty acids and facilitated fatty acid β-oxidation (FAO) of mice. The significant increase of carnitine palmitoyltransferase 1 (CPT1) and downregulation of acetyl-CoA acyltransferase 2 (ACAA2) would promote FAO in EI process induced by nitrosamines. Additionally, the exposure levels of more than half of nitrosamines in urine were correlated with inflammatory fatty acid biomarkers. Overall, this study found that EI triggered by nitrosamines may be associated with the promotion of FAO, and provided novel insights for evaluating the underlying mechanism of environmental pollutant-caused toxicity based on metabolomics.