Review articleThe role of gut microbiome in chemical-induced metabolic and toxicological murine disease models
Graphical abstract
Introduction
The global burden of metabolic disease is at epidemic proportion. The key concepts of intestinal etiology of metabolic disease have emerged out of our understanding of calorie overload. Purified high fat (HF)-diets can be used to induced various metabolic conditions such as obesity, diabetes and non-alcoholic fatty liver disease in experimental rodent models, which to a larger extent have comparable pathophysiological phenotypes to human metabolic conditions. Data suggested that altered gut microbiota and their increased energy harvesting capacity due to prolonged HF-feeding is associated with weight gain [1] (Fig. 1A). Furthermore, HF diet-induced altered gut microbiota potentiates metabolic endotoxemia that in turn promotes ‘low-grade’ systemic inflammation, a hallmark of obesity and diabetes [2]. Systemic (e.g. toll-like receptor-4) and intestinal (e.g. epithelial tight junction) targets have been identified [3,4], with supportive clinical evidences [5,6], have established that the etiology of metabolic disease are primarily intestine derived where gut microbiota plays profound role in potentiating and mediating metabolic anomalies (Fig. 1B). Thus intestine-centric prophylactic strategies have been proposed to mitigate these metabolic complications along the gut-systemic axis.
Since the advent of our understanding of gut-microbial biotransformation of drugs and phytochemicals responsible for altered bioactivity and bioavailability [7,8], in vivo models have become quintessential for pharmacological exploration of experimental drugs. Indeed, rats and mice collectively corresponds to >77% share of in vivo functional studies [9]. While HF-diet is a gold-standard for investigational chronic metabolic studies, chemical-induced acute metabolic disease models also serve as a reliable and cost-effective means for exploring and understanding the etiology of metabolic complications and for testing of prospective pharmacological drugs.
As discussed below, historically, the mode of actions of chemical-induced metabolic disease models have been attributed to direct tissue toxicity. Especially during the last few decades, our in-depth understanding of redox homeostasis has emphasized the tissue-level effects of the chemical-induced disease models primarily to be oxidative and pro-inflammatory insult-mediated cellular death. For example, carbon tetrachloride (CCl4), that is extensively used to induce liver cirrhosis, triggers oxidative hepatic injury through its derivative trichloromethyl radical. However, recent evidence indicate alternative and additional mechanisms through which CCl4-dependent hepatic injury could be in part associated with alterations in gut microbial phenotype. Indeed, this is true for several of chemical-induced metabolic disease models, indicating the mode of action of these chemicals are in-part dependent on gut microbiota.
The pivotal role of gut microbiota in human health, disease and every other physiological aspect is well established. While recent plethora of evidence suggests important role of intestinal microflora in chemical-induced disease models, a systematic and comprehensive account of those evidences are lacking in the literature. This is concerting since without addressing the microbiota-associated factors in experimental metabolic models, pharmacological studies would only treat symptoms, rather than the root of disease. Thus, this review is aimed to summarize the experimental evidences indicating microbiota-dependent alternative mode of action of metabolic disease models. Collectively, this review of recent evidences supporting microbial interventions in chemical-induced disease models would allow future investigators to emphasize more on microbial effects in pharmacological interventions upstream to tissue-specific metabolic complications and may serve as a reference for future chemical-induced pharmacological interventions.
Section snippets
Diet-induced metabolic disease model- the benchmark of microbiome research
Diet has emerged as the key modulator of gut microbiota and diet-induced metabolic disease models are considered as the gold-standard for in vivo pharmacological investigation of new drugs. Substantial evidence show that 60% (w/w) HF diet-induce an array of metabolic abnormalities including obesity, fatty-liver and insulin resistance (IR) [[10], [11], [12], [13], [14]]. On HF-diet, hyperglycemia appears at 4-wk [15], fat-accumulation accelerates at 8-wk [16] and histopathological symptoms of
Carbon tetrachloride (CCl4)-induced liver cirrhosis
The classical CCl4-induced hepatotoxicity (Fig. 2) is mediated by trichloromethyle radical (CCl3) that is generated through cytochrome P450-dependent reductive dehalogenation of CCl4 [26,27]. CCl3 triggers a cascade of intracellular changes that ultimately leads to oxidative and inflammatory stress-mediated hepatotoxicity. Further downstream generation of highly reactive trichloromethylperoxy radical (CCl3OO) induces direct intracellular injury, exacerbating the hepatoxicity. Although, CCl4 in
Diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC)
DEN is a hepatocellular carcinogen that potentiates HCC along the inflammation-fibrosis-cancer axis [50] (Fig. 3). DEN is one of the most reliable hepatocellular carcinogen that is used alone or in combination with other hepatotoxins (e.g. CCl4) or chronic inducers of metabolic anomalies (e.g. HF diet) to study an array of pathological, inflammatory and oncological parameters related to HCC [51]. HCC development depends on rodent age and sex, where younger and male mice are more susceptible to
Acetaminophen-induced hepatotoxicity
Acetaminophen, commonly known as Paracetamol, is an analgesic and antipyretic drug, overdose of which is attributed to >40% of all cases of drug-induced hepatotoxicity in the United States [64]. Key symptoms of acetaminophen-overdose include mild hepatitis, cholestasis and asymptomatic transaminase elevations, and could account for about 50% cases of acute liver failure [65]. Acetaminophen is frequently used in evidence-based in vivo pharmacology as hepatotoxic agent to evaluate the
Alloxan-induced diabetes
Alloxan (5,5-dihydroxyl pyrimidine-2,4,6-trione) is a urea derivative and a glucose analogue, that is extensively used as an insulin-dependent diabetogenic agent in pharmacological studies [77]. The diabetogenic activity of alloxan is through direct pancreatic β-cell toxicity (Fig. 5), thereby lowering insulin production and increasing systemic glucose load. In particular alloxan-treatment induce two separate pathological events viz. selective inhibition of glucose-induced insulin secretion and
Streptozotocin (STZ)-induced diabetes
STZ is a cytotoxic glucose analogue, that has been initially used as chemotherapeutic alkylating agent for treating metastasizing pancreatic islet cell tumors [95]. Since the discovery of its diabetogenic properties, STZ is extensively used to induce experimental diabetes in pharmacological studies (Fig. 6). The central element of STZ-induced diabetes is GLUT 2-dependent uptake into pancreatic β-cells and subsequent induction of apoptosis via DNA fragmentation due to the nitrosourea moiety in
Conclusions and perspectives
Data obtained from HF-induced obese murine model has been the primary source of knowledge of intestinal bacterial ecology. Yet, no absolute microbial marker of ‘dysbiosis’ and that of ‘healthy microbiota’ exists. Thus, it would be partially unfair to compare the intestinal-level microbial changes of clinical or HF-induced metabolic conditions to that of chemical-induced ones. In line, although the aforementioned evidences of chemical-induced disease models indicate a central role of gut
Abbreviations
- O2
superoxide radical
- OH
hydroxyl radical
- ALT
alanine aminotransferase
- CCl3
trichloromethyle radical
- CCl3OO
trichloromethylperoxy radical
- CCl4
carbon tetrachloride
- CD
cognitive dysfunction
- CYP2E1
cytochrome P450 2E1
- DEN
diethylnitrosamine
- F:B
Firmicutes-to-Bacteroidetes ratio
- Fe2+
ferrous ion
- GF
germ free
- GLP-1
glucagon-like peptide-1
- GLT2
glucose transporter 2
- GSH
Glutathione
- GSSH
Glutathione oxidized
- H2O2
hydrogen peroxide
- HCC
hepatocellular carcinoma
- HF
high fat
- IL
interleukin
- IR
insulin resistance
- JAK/STAT
janus kinases/signal
Declaration of competing interest
The author declares that he has no conflict of interest.
Acknowledgements
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
References (107)
Gut microbiota in phytopharmacology: a comprehensive overview of concepts, reciprocal interactions, biotransformations and mode of actions
Pharmacol. Res.
(2019)The pharmaco-toxicological conundrum of oleander: potential role of gut microbiome
Biomed. Pharmacother.
(2020)- et al.
Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation
J. Nutr. Biochem.
(2019) - et al.
Epigallocatechin gallate but not catechin prevents nonalcoholic steatohepatitis in mice similar to green tea extract while differentially affecting the gut microbiota
J. Nutr. Biochem.
(2020) - et al.
Mechanisms of carbon tetrachloride toxicity
Pharmacol. Ther.
(1989) - et al.
Assessment of hepatoprotective potential of N. indicum leaf on haloalkane xenobiotic induced hepatic injury in Swiss albino mice
Chem. Biol. Interact.
(2015) - et al.
Dysbiosis of gut microbiota in promoting the development of colorectal cancer
Gastroenterol Rep (Oxf)
(2018) - et al.
A prospective study of bacterial infections in patients with cirrhosis
J. Hepatol.
(1993) - et al.
Bacterial translocation of enteric organisms in patients with cirrhosis
J. Hepatol.
(2001) - et al.
Profound impact of gut homeostasis on chemically-induced pro-tumorigenic inflammation and hepatocarcinogenesis in rats
J. Hepatol.
(2012)
Promotion of hepatocellular carcinoma by the intestinal microbiota and TLR4
Cancer Cell
Intestinal epithelial chemokine (C-C motif) ligand 7 overexpression enhances acetaminophen-induced hepatotoxicity in mice
Am. J. Pathol.
Gut microbiota mediates diurnal variation of acetaminophen induced acute liver injury in mice
J. Hepatol.
Intestinal microbiota modulates susceptibility to acetaminophen induced acute liver injury
J. Hepatol.
The role of intestinal microflora in the formation of the methylthio adduct metabolites of paracetamol
Studies in neomycin-pretreated and germ-free mice, Biochem Pharmacol
Alloxan-induced diabetes, a common model for evaluating the glycemic-control potential of therapeutic compounds and plants extracts in experimental studies
Medicina (Kaunas, Lithuania)
Acacia nilotica leaf improves insulin resistance and hyperglycemia associated acute hepatic injury and nephrotoxicity by improving systemic antioxidant status in diabetic mice
J. Ethnopharmacol.
Assessment of anti-diabetic activity of an ethnopharmacological plant Nerium oleander through alloxan induced diabetes in mice
J. Ethnopharmacol.
Genistein enhances the secretion of glucagon-like peptide-1 (GLP-1) via downregulation of inflammatory responses
Biomed. Pharmacother.
Altered bile acid metabolism in alloxan diabetic rats
Jpn. J. Pharmacol.
The gut microbiota as an environmental factor that regulates fat storage
Proc. Natl. Acad. Sci. U. S. A.
Changes in gut microbiota control metabolic endotoxemia-induced inflammation in high-fat diet-induced obesity and diabetes in mice
Diabetes, 57
Toll-like receptor 4 signaling in liver injury and hepatic fibrogenesis
Fibrogenesis Tissue Repair
Intestinal barrier function: molecular regulation and disease pathogenesis
J. Allergy Clin. Immunol.
Mechanisms regulating intestinal barrier integrity and its pathological implications
Exp. Mol. Med.
Toll-like receptor status in obesity and metabolic syndrome: a translational perspective
The Journal of Clinical Endocrinology & Metabolism
Classification and analysis of a large collection of in vivo bioassay descriptions
PLoS Comput. Biol.
Joshua D. McDonald, Joshua B. Kim, Richard S. Bruno, green tea extract protects against hepatic NFκB activation along the gut-liver axis in diet-induced obese mice with nonalcoholic steatohepatitis by reducing endotoxin and TLR4/MyD88 signaling
J. Nutr. Biochem.
Use of high-fat diets to study rodent obesity as a model of human obesity
Int. J. Obes.
Green tea extract inhibits early oncogenic responses in mice with nonalcoholic steatohepatitis
Food Funct.
Antiobesity effect of eicosapentaenoic acid in high-fat/high-sucrose diet-induced obesity: importance of hepatic lipogenesis
Diabetes
C57BL/6J mice as a polygenic developmental model of diet-induced obesity
Physiological reports
Obese diet-induced mouse models of nonalcoholic steatohepatitis-tracking disease by liver biopsy
World J. Hepatol.
Female mice are protected against high-fat diet induced metabolic syndrome and increase the regulatory T cell population in adipose tissue
PLoS One
Female mice are more susceptible to nonalcoholic fatty liver disease: sex-specific regulation of the hepatic AMP-activated protein kinase-plasminogen activator inhibitor 1 cascade, but not the hepatic endotoxin response
Mol. Med.
Macronutrient diet selection in thirteen mouse strains
American journal of physiology. Regulatory, integrative and comparative physiology
An obesity-associated gut microbiome with increased capacity for energy harvest
nature
Women with and without metabolic disorder differ in their gut microbiota composition
Obesity (Silver Spring)
High fat diet-induced gut microbiota exacerbates inflammation and obesity in mice via the TLR4 signaling pathway
PLoS One
High-fat diet determines the composition of the murine gut microbiome independently of obesity
Gastroenterology
High-fat diet-induced obesity in animal models
Nutr. Res. Rev.
Hepatotoxicity and mechanism of action of haloalkanes: carbon tetrachloride as a toxicological model
Crit. Rev. Toxicol.
Hepatoprotective Effect of Barringtonia Acutangula Linn. Leaves on Carbon Tetrachloride-induced Acute Liver Damage in Rats
Haloalkane induced hepatic insult in murine model: amelioration by oleander through antioxidant and anti-inflammatory activities, an in vitro and in vivo study
BMC Complement. Altern. Med.
Mechanism of carbon tetrachloride-induced hepatotoxicity. Hepatocellular damage by reactive carbon tetrachloride metabolites
Zeitschrift fur Naturforschung. C, Journal of biosciences
Radical scavenging activities of Lagerstroemia speciosa (L.) Pers. petal extracts and its hepato-protection in CCl4-intoxicated mice
BMC Complement. Altern. Med.
Amelioration of CCl4 induced liver injury in swiss albino mice by antioxidant rich leaf extract of Croton bonplandianus Baill
PLoS One
Consumption of goats’ milk protects mice from carbon tetrachloride-induced acute hepatic injury and improves the associated gut microbiota imbalance
Front. Immunol.
A core gut microbiome in obese and lean twins
Nature
Microbial ecology: human gut microbes associated with obesity
Nature
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