Oxide In Mice Research Articles

Therapeutic Potential of <i>Persea americana </i>Stem Bark in Lipopolysaccharide (LPS) Induced Hepatic Inflammation and Oxidative Stress in Mice

This study investigated the potential of <i>Persea americana</i> stem bark for the treatment of inflammation and oxidation in mice. Oxidative stress occurs in the body when there is serious imbalance between the generation of free radicals and the antioxidant defense system, inflammation is a natural defense mechanism against pathogens and it is associated with many pathogenic diseases such as microbial and viral infections, exposure to allergens, radiation and toxic chemicals, autoimmune and chronic diseases, obesity, consumption of alcohol, tobacco use, and a high-calorie diet. Plants offer significant potentials for development of new anti-inflammatory therapies and treatment of diseases associated with inflammation and Oxidation. Stem bark of <i>Persea ameriacna</i> was extracted using EtOH/H<sub>2</sub>O (80:20 v/v), the extract obtained was subjected to maceration using 3 different solvents, hexane fraction (PAHF), Ethyl-acetate fraction (PAEF) and methanol fraction (PAMF). The methanol fraction came out with the highest yield and was used for the animal study, 30 male mice was divided into 3 different groups, LPS was introduced in one of the groups, PAMF was later administered to the same group, The experiment shows that the extract was able to demonstrate significant reduction in inflammation and also ameliorate oxidation in mice. In conclusion the methanolic fraction of <i>Persea americana</i> stem bark might contain beneficial phytochemicals that can be explored as potential anti-inflammatory and oxidative therapy.

Immature carob pods extract and its fractions prevent lipid metabolism disorders and lipoprotein-rich plasma oxidation in mice: A phytochemical and pharmacological study

Ethnopharmacological relevance: In Morocco carob fruits are used traditionally to treat hypercholesterolemia, diabetes and related diseases. Aims: This study was designed to evaluate the hypolipidemic activity of Ceratonia siliqua green pods extract and its fractions in Triton WR-1339 and high fat/cholesterol diet (HFCD) induced hyperlipidemia mice, as well as their ability to prevent lipoproteins oxidation in vitro. Materials and methods: High performance liquid chromatography (HPLC) analysis was used to determine the phenolic composition of the immature carob pods extract (HWCE). Antioxidant activities were evaluated using the DPPH radical scavenging test as well as MDA measurement in oxidized lipoprotein rich plasma. Plasma lipids, glucose and biliary total cholesterol, as well as lipids level in liver and feces, were analyzed. The acute oral toxicity was performed in mice single dosed with the HWCE at 2000 and 5000 mg/kg body weight. Results: HPLC analysis shows that gallic acid is the main phenolic compound in the HWCE. The acute oral toxicity assessment revealed that the HWCE is not toxic (LD50 is greater than 5000 mg/kg body weight). In the acute hypolipidemic study, mice treated with the HWCE and its fractions exhibited a significant (P < 0.001) reduction in plasma total cholesterol (TC), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-C) levels. Importantly, immature carob aqueous extract was more effective in lowering mice hypercholesterolemia than its fractions. Indeed, mice fed the HFCD for 12 weeks showed a significant raise in plasma TC, TG and LDL-C, as well as in hepatic and fecal TC and TG levels. The HWCE at 100 and 200 mg/kg body weight significantly (P < 0.001) reversed the plasmatic levels of these lipid parameters, increased plasma HDL-C level, reduced hepatic lipids accumulation, but increased cholesterol level in the bile and fecal lipids excretion. The HWCE decreased also the atherogenic index, the LDL-C/HDL-C ratio and plasma glucose level after 12 weeks’ experiment. On the other hand, the HWCE was more effective in preventing mice lipoprotein-rich plasma oxidation than its fractions, with a concentration-dependent manner. Conclusion: C. siliqua green fruits extract could be effective in preventing atherosclerosis and related cardiovascular complications through the inhibition of lipoprotein oxidation and cholesterol clearance.

PPARα agonist fenofibrate prevents postoperative cognitive dysfunction by enhancing fatty acid oxidation in mice.

Due to high rates of incidence and disability, postoperative cognitive dysfunction (POCD) currently receives a lot of clinical attention. Disturbance of fatty acid oxidation is a potential pathophysiological manifestation underlying POCD. Peroxisome proliferator-activated receptor α (PPARα) is a significant transcription factor of fatty acid oxidation that facilitates the transfer of fatty acids into the mitochondria for oxidation. The potential role of PPARα intervention in POCD warrants consideration. The present study is aimed to investigate whether PPARα agonist fenofibrate (FF) could protect long-term isoflurane anesthesia-induced POCD model and to explore the potential underlying function of fatty acid oxidation in the process. We established the POCD model via 6 h long-term isoflurane anesthesia in vivo with C57BL/6J mice and in vitro with N2a cells. Cells and mice were pretreated with PPARα agonist FF before anesthesia, after which fatty acid oxidation and cognitive function were assessed. The level of fatty acid oxidation-related proteins was determined using western blotting. The contextual fear conditioning test was utilized to evaluate mice's learning and memory. Our results showed that 6 h long-term isoflurane anesthesia induced contextual memory damage in mice, accompanied by decreases of fatty acid oxidation-related proteins (peroxisome proliferator-activated receptor γ coactivator 1α, carnitine palmitoyltransferase 1A, and PPARα) both in the hippocampus of POCD mice and in N2a cells. In the N2a cell model, pretreatment of PPARα agonist FF led to the upregulation of fatty acid oxidation-related proteins. In vivo results showed that preconditioned FF reached similar effects. More crucially, FF has been shown to reduce cognitive damage in mice after long-term isoflurane anesthesia. Additionally, our data showed that after blocking fatty acid oxidation by Etomoxir, FF failed to protect cognitive function from long-term isoflurane anesthesia. Pretreatment of PPARα agonist FF can protect against long-term isoflurane anesthesia-induced POCD by enhancing fatty acid oxidation.

The probiotic fermented milk of Lacticaseibacillus paracasei JY062 and Lactobacillus gasseri JM1 alleviates constipation via improving gastrointestinal motility and gut microbiota

Constipation is directly related to the intestinal microenvironment, in which the promotion of gastrointestinal (GI) motility and improvement of gut microbiota distribution are important for alleviating symptoms. Herein, after the intervention of probiotic fermented milk (FMMIX) containing Lacticaseibacillus paracasei JY062 and Lactobacillus gasseri JM1 for 14 d in Kunming mice with loperamide-induced constipation, the results indicated that FMMIX significantly increased the secretion of serum motilin, gastrin and 5-hydroxytryptamine, as well as decreased the secretion of peptide YY, vasoactive intestinal peptide, and nitric oxide in mice. As determined by immunohistochemical analysis, FMMIX promoted an augmentation in the quantity of Cajal interstitial cells. In addition, the mRNA and protein expression of c-kit and stem cell factor (SCF) were upregulated to facilitate intestinal motility. High-throughput sequencing and gas chromatography techniques revealed that FMMIX led to an increase in the relative abundance of beneficial bacteria (Lactobacillus, Oscillospira, Ruminococcus, Coprococcus, and Akkermansia), reduced the presence of harmful bacteria (Prevotella), and resulted in elevated levels of short-chain fatty acids (SCFA) with a superior improvement compared with unfermented milk. Untargeted metabolomics revealed significant upregulation of functional metabolites such as l-pipecolinic acid, dl-phenylalanine, and naringenin in FMMIX, presumably playing a potential role in constipation relief. Overall, our results showed that FMMIX had the potential to alleviate constipation symptoms in mice by improving the secretion of serum GI regulatory peptides and neurotransmitters, increasing the expression of c-kit and SCF proteins, and modulating the gut microbiota structure and SCFA levels, and may be associated with an increase in these functional metabolites. This suggested that FMMIX could be a promising adjunctive strategy for managing constipation symptoms and could contribute to the development of functional foods aimed at improving gut health.

The role of Keap1/Nrf2/HO-1 signal pathway in liver injury induced by rare earth neodymium oxide in mice

Objective: To investigate the role of Keap1/Nrf2/HO-1 signaling pathway in liver injury induced by neodymium oxide (Nd(2)O(3)) in mice. Methods: In March 2021, forty-eight SPF grade healthy male C57BL/6J mice were randomly divided into control group (0.9% NaCl), low dose group (62.5 mg/ml Nd(2)O(3)), medium dose group (125.0 mg/ml Nd(2)O(3)), and high dose group (250.0 mg/ml Nd(2)O(3)), each group consisted of 12 animals. The infected groups were treated with Nd(2)O(3) suspension by non-exposed tracheal drip and were killed 35 days after dust exposure. The liver weight of each group was weighed and the organ coefficient was calculated. The content of Nd(3+) in liver tissue was detected by inductively coupled plasma mass spectrometry (ICP-MS). HE staining and immunofluorescence was used to observe the changes of inflammation and nuclear entry. The mRNA expression levels of Keap1, Nrf2 and HO-1 in mice liver tissue were detected by qRT-PCR. Western blotting was used to detect the protein expression levels of Keap1 and HO-1. The contents of catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were detected by colorimetric method. The contents of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. The data was expressed in Mean±SD. Two-independent sample t-test was used for inter-group comparison, and one-way analysis of variance was used for multi-group comparison. Results: Compared with the control group, the liver organ coefficient of mice in medium and high dose groups were increased, and the Nd(3+) accumulation in liver of mice in all dose groups were significantly increased (P<0.05). Pathology showed that the structure of liver lobules in the high dose group was slightly disordered, the liver cells showed balloon-like lesions, the arrangement of liver cell cords was disordered, and the inflammatory exudation was obvious. Compared with the control group, the levels of IL-1β and IL-6 in liver tissue of mice in all dose groups were increased, and the levels of TNF-α in liver tissue of mice in high dose group were increased (P<0.05). Compared with the control group, the mRNA and protein expression levels of Keap1 in high dose group were significantly decreased, while the mRNA expression level of Nrf2, the mRNA and protein expression levels of HO-1 were significantly increased (P<0.05), and Nrf2 was successfully activated into the nucleus. Compared with the control group, the activities of CAT, GSH-Px and T-SOD in high dose group were significantly decreased (P<0.05) . Conclusion: A large amount of Nd(2)O(3) accumulates in the liver of male mice, which may lead to oxidative stress and inflammatory response through activation of Keap1/Nrf2/HO-1 signal pathway. It is suggested that Keap1/Nrf2/HO-1 signal pathway may be one of the mechanisms of Nd(2)O(3) expose-induced liver injury in mice.

Deglutarylation of glutaryl-CoA dehydrogenase by deacylating enzyme SIRT5 promotes lysine oxidation in mice

A wide range of protein acyl modifications has been identified on enzymes across various metabolic processes; however, the impact of these modifications remains poorly understood. Protein glutarylation is a recently identified modification that can be nonenzymatically driven by glutaryl-CoA. In mammalian systems, this unique metabolite is only produced in the lysine and tryptophan oxidative pathways. To better understand the biology of protein glutarylation, we studied the relationship between enzymes within the lysine/tryptophan catabolic pathways, protein glutarylation, and regulation by the deglutarylating enzyme sirtuin 5 (SIRT5). Here, we identify glutarylation on the lysine oxidation pathway enzyme glutaryl-CoA dehydrogenase (GCDH) and show increased GCDH glutarylation when glutaryl-CoA production is stimulated by lysine catabolism. Our data reveal that glutarylation of GCDH impacts its function, ultimately decreasing lysine oxidation. We also demonstrate the ability of SIRT5 to deglutarylate GCDH, restoring its enzymatic activity. Finally, metabolomic and bioinformatic analyses indicate an expanded role for SIRT5 in regulating amino acid metabolism. Together, these data support a feedback loop model within the lysine/tryptophan oxidation pathway in which glutaryl-CoA is produced, in turn inhibiting GCDH function via glutaryl modification of GCDH lysine residues and can be relieved by SIRT5 deacylation activity.

Effect of dietary dihydromyricetin supplementation on lipid metabolism, antioxidant capacity and skeletal muscle fiber type transformation in mice

This study aimed to investigate the effect of dietary dihydromyricetin (DHM) supplementation on lipid metabolism, antioxidant capacity and muscle fiber type transformation. Twenty-four male Kunming mice were randomly allotted to either control (basal diet) or DHM diets (supplemented with 300 mg/kg DHM). Our data showed that DHM administration decreased the triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) contents, and increased the catalase (CAT), total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities in serum. In the liver, DHM decreased the TG and malondialdehyde (MDA) levels and increased the T-SOD and GSH-Px activities. For the tibialis anterior (TA) muscle, DHM increased the total antioxidant capacity (T-AOC) level and T-SOD activities. Western blotting and real-time quantitative PCR analysis showed that DHM increased the protein and mRNA levels of MyHC I and MyHC IIa and decreased the protein and mRNA levels of MyHC IIb in TA muscle, which may be achieved by activating the AMP-activated protein kinase (AMPK) signal. The mRNA levels of several regulatory factors related to mitochondrial function were up-regulated by DHM. In conclusion, dietary 300 mg/kg DHM supplementation improved lipid metabolism and antioxidant capacity and promoted the transformation of muscle fiber type from glycolysis to oxidation in mice.

Antioxidant activity of Lactobacillus plantarum NJAU-01 in an animal model of aging

BackgroundExcessive reactive oxygen species (ROS) can cause serious damage to the human body and may cause various chronic diseases. Studies have found that lactic acid bacteria (LAB) have antioxidant and anti-aging effects, and are important resources for the development of microbial antioxidants. This paper was to explore the potential role of an antioxidant strain, Lactobacillus plantarum NJAU-01 screened from traditional dry-cured meat product Jinhua Ham in regulating D-galactose-induced subacute senescence of mice. A total of 48 specific pathogen free Kun Ming mice (SPF KM mice) were randomly allocated into 6 groups: control group with sterile saline injection, aging group with subcutaneously injection of D-galactose, treatments groups with injection of D-galactose and intragastric administration of 107, 108, and 109 CFU/mL L. plantarum NJAU-01, and positive control group with injection of D-galactose and intragastric administration of 1 mg/mL Vitamin C.ResultsThe results showed that the treatment group of L. plantarum NJAU-01 at 109 CFU/mL showed higher total antioxidant capacity (T-AOC) and the antioxidant enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) than those of the other groups in serum, heart and liver. In contrast, the content of the oxidative stress marker malondialdehyde (MDA) showed lower levels than the other groups (P < 0.05). The antioxidant capacity was improved with the supplement of the increasing concentration of L. plantarum NJAU-01.ConclusionsThus, this study demonstrates that L. plantarum NJAU-01 can alleviate oxidative stress by increasing the activities of enzymes involved in oxidation resistance and decreasing level of lipid oxidation in mice.

Toxicokinetic evaluation of the common indoor air pollutant, α-pinene, and its potential reactive metabolite, α-pinene oxide, following inhalation exposure in rodents

The toxicokinetic behavior of α-pinene and its potential reactive metabolite, α-pinene oxide, was investigated following whole body inhalation exposure to 50 and 100 ppm α-pinene in rats and mice for 6 h per day for 7d. In both species and sexes, the maximum blood concentration (Cmax) increased more than proportionally while the increase in area under the concentration time curve (AUC) was proportional to the exposure concentration. When normalized to the calculated dose (D), both Cmax/D (male rats, 12.2–54.5; female rats, 17.4–74.1; male mice, 7.41–14.2; female mice, 6.59–13.0 (ng/mL)/(mg/kg)) and AUC/D (male rats, 28.9–31.1; female rats, 55.8–56.8; male mice, 18.1–19.4; female mice, 19.2–22.5 (h*ng/mL)/(mg/kg)) in rats were higher than in mice and in female rats were higher than in male rats; no sex difference was observed in mice. α-Pinene was eliminated from blood with half-lives between 12.2 and 17.4 h in rats and 6.18–19.4 h in mice. At the low dose, the ratio of α-pinene oxide to α-pinene, based on Cmax and AUC, respectively, was 0.200–0.237 and 0.279–0.615 in rats and 0.060–0.086 and 0.036–0.011 in mice demonstrating lower formation of the oxide in mice than in rats. At the high dose, the ratio decreased considerably in both species pointing to saturation of pathways leading to the formation of α-pinene oxide. α-Pinene and the oxide were quantified in the mammary glands of rats and mice with tissue to blood ratios of ≥23 demonstrating retention of these analytes in mammary glands. The findings of epoxide formation and species- and sex-differences in systemic exposure may be important in providing context and relating animal findings to human exposures.

The Impact of Antarctic Ice Microalgae Polysaccharides on D-Galactose-Induced Oxidative Damage in Mice

Antarctic ice microalgae (Chlamydomonas sp.) are a polysaccharide-rich natural marine resource. In this study, we evaluated the impact of Antarctic ice microalgae polysaccharides (AIMP) on D-galactose-induced oxidation in mice. We conducted biological and biochemical tests on tissue and serum samples from mice treated with AIMP. We found that AIMP administration was associated with improved thymus, brain, heart, liver, spleen, and kidney index values. We also found that AIMP treatment inhibited the reduced aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, superoxide dismutase, glutathione peroxidase, and glutathione levels as well as the increased serum, splenic, and hepatic nitric oxide and malondialdehyde levels arising from oxidation in these animals. Pathological examination revealed that AIMP also inhibited D-galactose-induced oxidative damage to the spleen, liver, and skin of these animals. AIMP was additionally found to promote the upregulation of neuronal nitric oxide synthase, endothelial nitric oxide synthase, cuprozinc-superoxide dismutase, manganese superoxide dismutase, catalase, heme oxygenase-1, nuclear factor erythroid 2-related factor 2, γ-glutamylcysteine synthetase, and NAD(P)H dehydrogenase [quinone] 1 as well as the downregulation of inducible nitric oxide synthase in these animals. High-performance liquid chromatography analysis revealed AIMP to be composed of five monosaccharides (mannitol, ribose, anhydrous glucose, xylose, and fucose). Together, these results suggest that AIMP can effectively inhibit oxidative damage more readily than vitamin C in mice with D-galactose-induced oxidative damage, which underscores the value of developing AIMP derivatives for food purposes.

An Oil Rich in γ-Linolenic Acid Differently Affects Hepatic Fatty Acid Oxidation in Mice and Rats.

The effects of different dietary fats on hepatic fatty acid oxidation were compared in male ICR mice and Sprague-Dawley rats. Animals were fed diets containing 100 g/kg of either palm oil (saturated fat), safflower oil (rich in linoleic acid), an oil of evening primrose origin (γ-linolenic acid, GLA oil), perilla oil (α-linolenic acid) or fish oil (eicosapentaenoic and doxosahexaenoic acids) for 21 d. GLA, perilla and fish oils, compared with palm and safflower oils, increased the activity of fatty acid oxidation enzymes in both mice and rats, with some exceptions. In mice, GLA and fish oils greatly increased the peroxisomal palmitoyl-CoA oxidation rate, and the activity of acyl-CoA oxidase and enoyl-CoA hydratase to the same degree. The effects were much smaller with perilla oil. In rats, enhancing effects were more notable with fish oil than with GLA and perilla oils, excluding the activity of enoyl-CoA hydratase, and were comparable between GLA and perilla oils. In mice, strong enhancing effects of GLA oil, which were greater than with perilla oil and comparable to those of fish oil, were confirmed on mRNA levels of peroxisomal but not mitochondrial fatty acid oxidation enzymes. In rats, the effects of GLA and perilla oils on mRNA levels of peroxisomal and mitochondrial enzymes were indistinguishable, and lower than those observed with fish oil. Therefore, considerable diversity in the response to dietary polyunsaturated fats, especially the oil rich in γ-linolenic acid and fish oil, of hepatic fatty acid oxidation pathway exists between mice and rats.

How bad is brazilian ginseng extract for reproductive parameters in mice?

Properties attributed to the Panax ginseng are also attributed to the Brazilian ginseng, such as adaptogenic and aphrodisiac effects. There are studies demonstrating that the Brazilian ginseng (BGE) possibly increases the serum levels of testosterone and nitric oxide in mice and rats. The present study aimed to evaluate the effects of its extract on male fertility and sperm quality. Male Swiss mice (n = 60) were divided into six groups. The control animals were provided 0.5 mL of water, and 0.5 mL of water containing 7 mg/kg per day (d) sildenafil citrate. Other animals were treated with BGE at 100 mg/kg/d, 200 mg/kg/d, and 400 mg/kg/d by gavage for 42 days. Finally, animals from the last group received 200 mg/kg BGE every 3 days (3-3d) by gavage for 42 days. The results showed a reduction in the number of resistant spermatids in the testis and damage to daily sperm production, culminating in a reduction in the number of epididymal spermatozoa. Although the sperm quality decreased in all experimental animals, only males treated with BGE 100 mg/kg/d showed pre and post implantation embryo losses. We concluded that BGE alters sperm viability compromising the embryonic development after implantation.

Hypoxic Exposure Increases Energy Expenditure by Increasing Carbohydrate Oxidation in Mice

Aims. Hypoxic exposure improves glucose metabolism. We investigated to validate the hypothesis that carbohydrate (CHO) oxidation could increase in mice exposed to severe hypoxic conditions.Methods. Seven-week-old male ICR mice (n=16) were randomly divided into two groups: the control group (CON) was kept in normoxic condition (fraction of inspiredO2=21%) and the hypoxia group (HYP) was exposed to hypoxic condition (fraction of inspiredO2=12%, ≈altitude of 4,300 m). The CON group was pair-fed with the HYP group. After 3 weeks of hypoxic exposure, we measured respiratory metabolism (energy expenditure and substrate utilization) at normoxic conditions for 24 hours using an open-circuit calorimetry system. In addition, we investigated changes in carbohydrate mechanism-related protein expression, including hexokinase 2 (HK2), pyruvate dehydrogenase (PDH), pyruvate dehydrogenase kinase 4 (PDK4), and regulator of the genes involved in energy metabolism (peroxisome proliferator-activated receptor gamma coactivator 1-alpha, PGC1α) in soleus muscle.Results. Energy expenditure (EE) and CHO oxidation over 24 hours were higher in the HYP group by approximately 15% and 34% (p&lt;0.001), respectively. Fat oxidation was approximately 29% lower in the HYP group than the CON group (p&lt;0.01). Body weight gains were significantly lower in the HYP group than in the CON group (CON vs. HYP;1.9±0.9vs.−0.3±0.9;p&lt;0.001). Hypoxic exposure for 3 weeks significantly reduced body fat by approximately 42% (p&lt;0.001). PDH and PGC1αprotein levels were significantly higher in the HYP group (p&lt;0.05). Additionally, HK2 was approximately 21% higher in the HYP group.Conclusions. Hypoxic exposure might significantly enhance CHO oxidation by increasing the expression of PDH and HK2. This investigation can be useful for patients with impaired glucose metabolism, such as those with type 2 diabetes.

Canagliflozin ameliorates obesity by improving mitochondrial function and fatty acid oxidation via PPARα in vivo and in vitro

AimsSodium-glucose cotransporter 2 (SGLT2) inhibitors have been reported to significantly reduce body weight. This study investigated whether SGLT2 inhibitors directly affect adipose tissues and the underlying mechanisms in vivo and in vitro. Main methodsMale C57BL/6 mice were fed a normal diet, high-fat diet (HFD), or HFD with canagliflozin for 14 weeks. 3T3-L1 adipocytes were treated with canagliflozin. Metabolic parameters were measured. Key findingsCanagliflozin reduced body weight, fat mass, and white adipose tissue (WAT) weight and inhibited adipocyte hypertrophy. Canagliflozin improved glucose and lipid metabolic disorders induced by HFD. Furthermore, canagliflozin treatment reversed the suppressed mRNA and protein expression of PGC-1α, NRF1, tfam and CPT1b, which are markers of mitochondrial biogenesis, function and fatty acid oxidation in mice with obesity. In vitro, canagliflozin increased mitochondrial DNA to nuclear DNA and upregulated the expression of PGC-1α, NRF1, tfam, COX5b, COX8b, Atp5o, and CPT1b mRNA and PGC-1α, NRF1, tfam, COX5b, CPT1b protein in 3T3-L1 adipocytes in a dose-dependent manner, while these increases were inhibited by GW6471, a PPARα antagonist. SignificanceOur study showed that canagliflozin protected against HFD-induced obesity and obesity-related metabolic disorders by improving mitochondrial function and fatty acid oxidation in adipose tissue and adipocytes. Such energy-dissipating effects of canagliflozin may be mediated by PPARα.

Effect of insect tea on D-galactose-induced oxidation in mice and its mechanisms.

Insect tea is a traditional Chinese drink that contains abundant bioactive substances. In this study, the preventive effect of Insect tea on D‐galactose‐induced oxidation in mice was studied. The serum, liver, and spleen of mice were measured by biochemical and molecular biological methods, which showed that Insect tea could increase the biochemical indexes of the thymus, brain, heart, liver, spleen, and kidney in mice with induced oxidative damage. Insect tea can increase the levels of SOD (superoxide dismutase), GSH‐Px (glutathione peroxidase), and GSH (glutathione) and decrease the levels of MDA (malondialdehyde) in the serum, liver, and spleen of mice with oxidative damage. Pathological observation also confirmed that Insect tea could inhibit oxidative damage of the liver and spleen tissue caused by D‐galactose in mice. Further molecular biological experiments also showed that Insect tea could upregulate the mRNA and protein expression of Cu/Zn‐SOD (cuprozinc‐superoxide dismutase), Mn‐SOD (manganese superoxide dismutase), CAT (catalase), HO‐1 (heme oxygenase‐1), Nrf2 (nuclear factor‐erythroid 2 related factor 2), γ‐GCS (γ‐glutamylcysteine synthetase), and NQO1 (NAD(P)H dehydrogenase [quinone] 1) in the liver and spleen of oxidized mice. Insect tea has a good preventive effect on D‐galactose‐induced oxidation in mice, and the effect is better than vitamin C, an antioxidant. Insect tea is rich in isochlorogenic acid A, quercetin, rutin, hesperidin, neochlorogenic acid, and cryptochlorogenic acid. The combination of these bioactive substances has good antioxidant effects. Thus, Insect tea is a functional food with a good antioxidant effect that has value for future development and utilization.

Extended indirect calorimetry with isotopic CO2 sensors for prolonged and continuous quantification of exogenous vs. total substrate oxidation in mice

Indirect calorimetry (InCa) estimates whole-body energy expenditure and total substrate oxidation based on O2 consumption and CO2 production, but does not allow for the quantification of oxidation of exogenous substrates with time. To achieve this, we incorporated 13CO2 and 12CO2 gas sensors into a commercial InCa system and aimed to demonstrate their performance and added value. As a performance indicator, we showed the discriminative oscillations in 13CO2 enrichment associated with food intake in mice fed diets containing naturally low (wheat) vs high (maize) 13C enrichment. To demonstrate the physiological value, we quantified exogenous vs total carbohydrate and fat oxidation continuously, in real time in mice varying in fat mass. Diet-induced obese mice were fed a single liquid mixed meal containing 13C-isotopic tracers of glucose or palmitate. Over 13 h, ~70% glucose and ~48% palmitate ingested were oxidised. Exogenous palmitate oxidation depended on body fat mass, which was not the case for exogenous glucose oxidation. We conclude that extending an InCa system with 13CO2 and 12CO2 sensors provides an accessible and powerful technique for real-time continuous quantification of exogenous and whole-body substrate oxidation in mouse models of human metabolic physiology.

(5R)-5-hydroxytriptolide ameliorates liver lipid accumulation by suppressing lipid synthesis and promoting lipid oxidation in mice

Aims(5R)-5-hydroxytriptolide (LLDT-8) is a triptolide analog with excellent capability against cancers, cerebral ischemic injury and rheumatoid arthritis. Here, we discovered its hepatoprotective effects in a mouse model of non-alcoholic fatty liver disease (NAFLD) by ameliorating liver lipid accumulation. Main methodsMale C57BL/6J mice were fed with a high-fat/high-fructose (HFHFr) diet for 29 weeks to induce the pathological phenomena of NAFLD. Then the mice were treated with LLDT-8 (0.5mg/kg and 1mg/kg) or Vehicle for 8 weeks. Finally, the serum biochemical indexes, liver histological features, fatty acids (FAs) profile and related gene expression in liver were detected to investigate the effect of LLDT-8 on lipid accumulation and its possible mechanism. Key findingsLLDT-8 treatment significantly inhibited hepatic injury featured by the decrease of serum alanine aminotransferase (ALT) and aspartate transaminase (AST), the lessening of hepatic ballooning and macrovesicular steatosis. Moreover, LLDT-8 could downregulate the expression of stearoyl-CoA desaturase 1 (SCD1), which further led to the lower ratios of C16:1/C16:0 and C18:1/C18:0 and thus inhibited lipid synthesis. LLDT-8 treatment also could upregulate liver peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1a (Cpt1a), peroxisomal acyl-CoA oxidase 1 (Acox1), long-chain acyl-CoA dehydrogenase (Acadl) and medium-chain acyl-CoA dehydrogenase (Acadm) expression levels involved in fatty acids oxidation (FAO) and markedly promoted lipolysis. SignificanceOur results provide a novel application of LLDT-8 in improving NAFLD.

Abstract SY28-02: Hyperinsulinemia mediates the effect of obesity to promote tumor growth in murine breast and colon cancer

Abstract Obesity is associated with an increased incidence of more than one dozen tumor types, and a poorer prognosis of most of these. Intriguingly, interventions which improve the metabolic phenotype of obese individuals – including exercise, weight loss, and treatment with metformin, the most commonly prescribed anti-diabetes drug in the world – slow tumor growth in animals and may have a tumor-slowing effect in humans. The mechanisms for this association have been the subject of numerous studies and are still an area of active debate. Here I will present data arguing that obesity-associated hyperinsulinemia resulting from insulin resistance drives tumor growth in murine models of colon and breast cancer by promoting tumor glucose uptake and oxidation, measured using novel stable isotope methods. In vitro studies reveal that these findings regarding the ability of hyperinsulinemia to drive glucose oxidation are generalizable across multiple human and mouse cell lines from obesity-associated tumors (prostate, breast, ovarian, colon, and pancreatic cancer) but not obesity-independent tumors (small cell lung cancer, melanoma, lymphoma, osteosarcoma). Of particular importance, three insulin-sensitizing and -lowering agents with divergent mechanisms of action slowed breast and colon tumor growth in an insulin-dependent manner: 1) dapagliflozin, a sodium-glucose contransporter-2 (SGLT2) inhibitor, which promotes glycosuria, 2) metformin, which inhibits gluconeogenesis, and 3) a functionally liver-targeted controlled-release mitochondrial protonophore (CRMP), which reverses non-alcoholic fatty liver disease by increasing hepatic mitochondrial oxidation, and thereby improves both hepatic and peripheral insulin sensitivity (the latter due to reduced very low-density lipoprotein export). Restoring hyperinsulinemia via continuous insulin infusion using subcutaneous pellets abrogated the effect of each agent to slow tumor growth. I will further show data indicating that both glucose uptake and oxidation in these obesity-associated tumors is insulin-responsive: diet-induced obesity, causing hyperinsulinemia, increased both glucose uptake and oxidation, whereas insulin-lowering interventions reversed these effects, and restoring hyperinsulinemia by subcutaneous insulin infusion increased tumor glucose uptake and oxidation in mice treated with insulin-lowering agents. These data are contrary to the commonly held view that tumor glucose uptake is constitutively high, and argue that rates of glucose oxidation in tumors may vary dynamically with the hormonal milieu. In summary, I will argue that hyperinsulinemia per semediates the majority of the effect of obesity to drive tumor growth in murine models of colon and breast cancer by increasing tumor glucose uptake and oxidation. These data highlight an important role for insulin-lowering therapies, some of which are already in the clinic (diet and exercise, in particular a ketogenic diet; metformin; SGLT2 inhibitors), and others of which are in preclinical development (liver-targeted mitochondrial uncouplers) to prevent or slow obesity-associated cancer progression. Citation Format: Rachel J. Perry. Hyperinsulinemia mediates the effect of obesity to promote tumor growth in murine breast and colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr SY28-02.

Defective fatty acid oxidation in mice with muscle-specific acyl-CoA synthetase 1 deficiency increases amino acid use and impairs muscle function

Loss of long-chain acyl-CoA synthetase isoform-1 (ACSL1) in mouse skeletal muscle (Acsl1M-/-) severely reduces acyl-CoA synthetase activity and fatty acid oxidation. However, the effects of decreased fatty acid oxidation on skeletal muscle function, histology, use of alternative fuels, and mitochondrial function and morphology are unclear. We observed that Acsl1M-/- mice have impaired voluntary running capacity and muscle grip strength and that their gastrocnemius muscle contains myocytes with central nuclei, indicating muscle regeneration. We also found that plasma creatine kinase and aspartate aminotransferase levels in Acsl1M-/- mice are 3.4- and 1.5-fold greater, respectively, than in control mice (Acsl1flox/flox ), indicating muscle damage, even without exercise, in the Acsl1M-/- mice. Moreover, caspase-3 protein expression exclusively in Acsl1M-/- skeletal muscle and the presence of cleaved caspase-3 suggested myocyte apoptosis. Mitochondria in Acsl1M-/- skeletal muscle were swollen with abnormal cristae, and mitochondrial biogenesis was increased. Glucose uptake did not increase in Acsl1M-/- skeletal muscle, and pyruvate oxidation was similar in gastrocnemius homogenates from Acsl1M-/- and control mice. The rate of protein synthesis in Acsl1M-/- glycolytic muscle was 2.1-fold greater 30 min after exercise than in the controls, suggesting resynthesis of proteins catabolized for fuel during the exercise. At this time, mTOR complex 1 was activated, and autophagy was blocked. These results suggest that fatty acid oxidation is critical for normal skeletal muscle homeostasis during both rest and exercise. We conclude that ACSL1 deficiency produces an overall defect in muscle fuel metabolism that increases protein catabolism, resulting in exercise intolerance, muscle weakness, and myocyte apoptosis.

Effects of dietary protein contents and habitual endurance exercise on supplemental leucine oxidation in mice.

The effects of dietary protein contents and regular exercise on the oxidation of supplemented leucine were examined. In the short-term study, male BALB/cCrSlc mice were fed diets containing 0, 10, 20, 35, and 60% protein: energy ratios for 1week. In the long-term study, exercised and sedentary mice were fed diets containing 20, 35, and 60% protein ratios for 9weeks. After the feeding periods, the mice were a bolus administered oral supplements of l-[1-13C] leucine. Expired gas was analyzed, and oxidized leucine was expressed as a relative 13CO2/12CO2 ratio. In the short-term study, the peak 13CO2/12CO2 ratio significantly increased with diet protein concentrations. Moreover, the long-term study also showed that the peak 13CO2/12CO2 ratio was significantly increased by high protein diets in both exercised and sedentary mice. Our results indicate that supplemental leucine oxidation is associated with consumption of a high-protein diet, irrespective of exercise status. Abbreviations: AUC: area under the curve; EX: exercise; RQ: respiratory quotient; SED: sedentary; VO2/W: oxygen uptake per body weight.