Obesity-induced diet leads to weight gain, systemic metabolic alterations, adipose tissue inflammation, hepatic steatosis, and oxidative stress in gerbils (Meriones unguiculatus)

Potential Hepatoprotective Effect of Matricaria Pubescens on High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease in Rats

This study aimed to identify the phytochemical compounds of Matricaria pubescens by LC-MS/MS and evaluate the potential protective effect of its supplementation in high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in adult rats through modulation of oxidative stress and histopathological changes. Twenty-four male rats were randomly divided into four groups. The first group served as control and received the standard diet. The second group (HFD) received a high-fat diet only (30 % of sheep fat). The third group's (control+MP) animals received a standard diet supplemented with 5 % M. pubescens (w/w). The fourth group (HFD+MP) received a high-fat diet supplemented with 5 % M. pubescens for 16 weeks. LC-MS/MS analysis showed that M. pubescens contains many phytochemical compounds. It was observed that the ethanolic extract of M. pubescens has a higher phenolic content than the aqueous extract. The supplementation of M. pubescens (5 % w/w) to HFD rats decreased significantly (p<0.01) body weight, liver and epididymal adipose tissue relative weights, glycemia, triglycerides (TG), insulin resistance, liver markers, TNF-α, malondialdehyde (MDA), protein carbonyl (PCO), advanced oxidation protein products (AOPP) level, and increased reduced glutathione (GSH) level, glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase activities as well as ameliorated histological alterations through the reduction hepatic lipid deposition and adipocytes hypertrophy compared to the HFD group. We conclude that M. pubescens powder may be effective for correcting hyperglycemia, hypertriglyceridemia, insulin resistance, and liver markers while decreasing inflammation and oxidative stress in the liver of high-fat diet-fed rats.

Interference of altered plasma trace elements profile with hyperhomocysteinemia and oxidative stress damage to insulin secretion dysfunction in Psammomys obesus: focus on the selenium

The objective of this study is to investigate the relationship between altered plasma trace elements, particularly selenium (Se), with Hyper-homocysteinemia (HhCys) as a predictive factor of insulin secretion dysfunction. The study is carried out on adult Psammomys obesus, divided in 4 experimental groups: (I) Normoglycemic/Normoinsulinemic; (II) Normoglycemic/Hyperinsulinemic; (III) Hyperglycaemic/Hyperinsulinemic and (IV) Hyperglycaemic/Insulin deficiency with ketoacidosis. The data showed that a drastic depletion of Se plasma levels is positively correlated with HhCys (>15 µmol/L; p < .001), concomitantly with decreased GPx activity, GSH levels, and GSH/GSSG ratio in group IV both in plasma and liver. In contrast, SOD activity is increased (p ≤ .001) in group IV both in plasma and liver. However, plasma Cu and Mn levels increased, while plasma Zn levels decreased in group IV (p < .001). Our study confirms the increase of plasma hCys levels seemed to be a major contributing factor to antioxidant capacities and alters the availability of selenium metabolism by interference with homocysteine synthesis in the insulin secretion deficiency stage.

Cardioprotective action of chia (Salvia hispanica L.) in ovariectomized rats fed a high fat diet

The reduction in estrogen levels is associated with the increased risk factors for cardiovascular disease development. The present study aimed to evaluate the effect of chia consumption in a standard diet (SD) or high fat diet (HFD) on ovariectomized (OVX) and non-ovariectomized (SHAM) rats, in relation to biometric measurements, oxidative stress, mineral content and ATPase enzymes in the heart. The study was conducted with 80 female Wistar rats, which received a SD or HFD for 18 weeks. During the first 7 weeks, the animals received the SD or HFD. Then, 40 rats were ovariectomized and 40 rats were SHAM operated. After recovery from surgery, the animals were allocated to 8 groups (n = 10) and they received one of the following diets for 8 weeks: SD, SD + chia, HFD and HFD + chia. In the OVX group, HFD increased weight gain, adiposity, cardiac hypertrophy, and nitric oxide (NO) and K concentration and decreased the Na⁺/K⁺ATPase activity. In combination with HFD, ovariectomy decreased the catalase activity, Mg, Cu and Zn concentration, total ATPase activity, and Na⁺/K⁺ATPase and Mg2 + ATPase activities; this group also presented higher NO, Ca, K, Fe and Mn concentration in the heart. The SHAM group fed chia presented a lower fat content in the heart. In the OVX group fed HFD, chia increased the activity of superoxide dismutase, decreased NO and maintained the content of minerals and ATPase enzymes. Thus, chia improved the biometric parameters of the heart, the antioxidant activity and maintained the content of minerals and ATPase enzymes, showing a cardioprotective action, but without reversing the deleterious effects of ovariectomy.

Oxidative stress does not influence weight loss induced by aerobic training in adults: randomized clinical trials

BACKGROUND

High levels of oxidative stress promote degradation of the cell membrane impairing cellular function in fat oxidation. However, the influence of oxidative stress on exercise-induced weight-loss has not yet been investigated. Therefore, the aim of this study was to verify the influence of a lipidic peroxidation marker (malondialdehyde, MDA) and antioxidant status (total antioxidant capacity marker, TAC) on the magnitude of weight-loss by aerobic-induced exercise in previously sedentary overweight or obese individuals.

METHODS

Seventy-five physically inactive adults were randomized into experimental (N.=58) and control (N.=17) groups, who engaged in a 12-week program of aerobic training walking and/or running (3 to 5 days/week) or stretching (1 day/week), respectively. Body composition (DXA), aerobic capacity (ergospirometric) and blood collections for oxidative stress analysis (MDA and TAC) were determined before and after the experimental protocol. Two-way ANOVA for repeated measures or Friedman's test were used to evaluate differences in time/group interaction. Pearson correlation was used to verify the relationship between the variables of oxidative stress and of body composition.

RESULTS

Significant reduction was found in fat body mass of experimental when compared to control group (-1.3±1.9 kg versus -0.3±1.3, P=0.04). Experimental group also altered significantly the total body mass (-1.2±4.7 kg; effect size 0.44), body mass index - BMI (-0.3±1.1 effect size 0.37), fat percentage (1.3±1.6%; effect size 0.50) and lean body mass (0.6±1.5 kg; effect size 0.32).There was increase in MDA of 2.3 μmol/L to 2.7 μmol/L (P=0.00), without changes to TAC (25.6±13.9% to 28.0±10.4%). No correlation was found between these variations in body composition with either the initial values of MDA and TAC or delta variation of these indicators of oxidative stress in response to the training program.

CONCLUSIONS

Indicators of oxidative stress (MDA and TAC) does not influence the magnitude of weight-loss induced by aerobic training.

A 2-Min Transient Ischemia Confers Cerebral Ischemic Tolerance in Non-Obese Gerbils, but Results in Neuronal Death in Obese Gerbils by Increasing Abnormal mTOR Activation-Mediated Oxidative Stress and Neuroinflammation

A brief episode of transient ischemia (TI) can confer cerebral ischemic tolerance against a subsequent severer TI under standard condition. The brain under obesity’s conditions is more sensitive to ischemic injury. However, the impact of a brief episode of TI under obesity’s conditions has not been fully addressed yet. Thus, the objective of this study was to determine the effect of a brief TI in the hippocampus of high-fat diet (HFD)-induced obese gerbils and related mechanisms. Gerbils were maintained on HFD or normal diet (ND) for 12 weeks and subjected to 2 min TI. HFD gerbils were heavier, with higher blood glucose, serum total cholesterol, triglycerides, and leptin levels. Massive loss of pyramidal neurons occurred in the hippocampal cornu ammonis 1 (CA1) field of HFD animals at 5 days after 2 min of TI, but 2 min of TI did not elicit death of pyramidal neurons in ND gerbils. The HFD group showed significantly increased levels of oxidative stress indicators (dihydroethidium and 4-hydroxynonenal) and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and microglial activation in pre- and/or post-ischemic phases compared to the ND group. Levels of mammalian target of rapamycin (mTOR) and phosphorylated-mTOR in the CA1 field of the HFD group were also significantly higher than the ND group. On the other hand, inhibition of mTOR activation by rapamycin (an allosteric mTOR inhibitor) significantly attenuated neuronal death induced by HFD, showing reduction of HFD-induced increases of oxidative stress indicators and proinflammatory cytokines, and microglia activation. Taken together, a brief episode of TI can evoke neuronal death under obesity’s conditions. It might be closely associated with an abnormal increase of mTOR activation-mediated, severe oxidative stress and neuroinflammation in pre- and/or post-ischemic phases.

Antioxidant Properties of Fucoidan Alleviate Acceleration and Exacerbation of Hippocampal Neuronal Death Following Transient Global Cerebral Ischemia in High-Fat Diet-Induced Obese Gerbils

Fucoidan, a natural sulfated polysaccharide, displays various biological activities including antioxidant properties. We examined the neuroprotective effect of fucoidan against transient global cerebral ischemia (tGCI) in high-fat diet (HFD)-induced obese gerbils and its related mechanisms. Gerbils received HFD for 12 weeks and fucoidan (50 mg/kg) daily for the last 5 days during HFD exposure, and they were subjected to 5-min tGCI. Pyramidal cell death was observed only in the CA 1 area (CA1) of the hippocampus in non-obese gerbils 5 days after tGCI. However, in obese gerbils, pyramidal cell death in the CA1 and CA2/3 occurred at 2 days and 5 days, respectively, after tGCI. In the obese gerbils, oxidative stress indicators (dihydroethidium, 8-hydroxyguanine and 4-hydroxy-2-nonenal) were significantly enhanced and antioxidant enzymes (SOD1 and SOD2) were significantly reduced in pre- and post-ischemic phases compared to the non-obese gerbils. Fucoidan treatment attenuated acceleration and exacerbation of tGCI-induced neuronal death in the CA1–3, showing that oxidative stress was significantly reduced, and antioxidant enzymes were significantly increased in pre- and post-ischemic phases. These findings indicate that pretreated fucoidan can relieve the acceleration and exacerbation of ischemic brain injury in an obese state via the attenuation of obesity-induced severe oxidative damage.

Chronic high-fat diet-induced obesity in gerbils increases pro-inflammatory cytokines and mTOR activation, and elicits neuronal death in the striatum following brief transient ischemia

Recent studies have shown that obesity and its related metabolic dysfunction exacerbate outcomes of ischemic brain injuries in some brain areas, such as the hippocampus and cerebral cortex when they are subjected to transient ischemia. However, the impact of obesity in the striatum after brief transient ischemia has not yet been addressed. The objective of this study was to investigate effects of obesity on neuronal damage and inflammation in the striatum after transient ischemia and to examine the role of mTOR which is involved in the pathogenesis of metabolic and neurological diseases. Gerbils were fed with normal diet (ND) or high-fat diet (HFD) for 12 weeks and subjected to 5 min of transient ischemia. HFD-fed gerbils showed significant increase in body weight, blood glucose level, serum triglycerides, total cholesterol and low-density lipoprotein cholesterol without affecting food intake. Neuronal death/loss in the HFD-fed gerbils occurred in the dorsolateral striatum 2 days after transient ischemia, and neuronal loss was increased 5 days after transient ischemia, although no neuronal loss was observed in ND-fed gerbils at any time after transient ischemia. The HFD-fed gerbils showed hypertrophied microglia and further increased expressions of tumor necrosis factor-alpha, interukin-1beta, mammalian target of rapamycin (mTOR) and phosphorylated-mTOR during pre- and post-ischemic phases compared with the ND-fed gerbils. Additionally, we found that treatment with mTOR inhibitor rapamycin in the HFD-fed gerbils significantly attenuated transient ischemia-induced neuronal death in the dorsolateral striatum. These findings reveal that chronic HFD-induced obesity results in severe neuroinflammation and significant increase of mTOR activation, which could contribute to neuronal death in the stratum following 5 min of transient ischemia. Especially, abnormal mTOR activation would play a key role in mediating obesity-induced severe ischemic brain injury.

Short-Term Administration of Astaxanthin Attenuates Retinal Changes in Diet-Induced Diabetic Psammomys obesus

OBJECTIVES

Psammomys obesus is a high-fat diet (HFD)-fed animal model of obesity and type 2 diabetes recently explored as a model of non-proliferative diabetic retinopathy. This study tested the protective effect of the pigment astaxanthin (AST) in the P. obesus diabetic retina.

METHODS

Young adult P. obesus were randomly assigned to two groups. The control group received a normal diet consisting of a plant-based regimen, and the HFD group received an enriched laboratory chow. After 3 months, control and diabetic rodents were administered vehicle or AST, daily for 7 days. Body weight, blood glucose, and plasma pentosidine were assessed. Frozen sections of retinas were immunolabeled for markers of oxidative stress, glial reactivity and retinal ganglion cell bodies, and imaged by confocal microscopy.

RESULTS

Retinal tissue from AST-treated control and HFD-diabetic P. obesus showed a greater expression of the antioxidant enzyme heme oxygenase-1 (HO-1). In retinas of HFD-diabetic AST-treated P. obesus, cellular retinaldehyde binding protein and glutamine synthetase in Müller cells were more intense compared to the untreated HFD-diabetic group. HFD-induced diabetes downregulated the expression of glial fibrillary acidic protein in astrocytes, the POU domain protein 3A in retinal ganglion cells, and synaptophysin throughout the plexiform layers.

DISCUSSION

Our results show that type 2-like diabetes induced by HFD affected glial and neuronal retinal cell homeostasis. AST treatment induced the antioxidant enzyme HO-1 and reduced glial reactivity. These findings suggest that diabetic P. obesus is a useful model of HFD-induced obesity and diabetes to evaluate early neuroglial retinal alterations and antioxidant neuroprotection mechanisms in DR.

Inhibition of adiposity and related metabolic disturbances by polyphenol-rich extract of Boswellia serrata gum through alteration of adipo/cytokine profiles

BACKGROUND

The role of proinflammatory cytokines in adiposity is well established. The anti-inflammatory and antihyperglycemia effects of Boswellia serrata (B. Serrata) gum have been demonstrated by many investigators. The present study aimed to investigate the anti-obesity potential of B. serrata extract.

METHODS

The effects of B. serrata extract on lipase activity and acute food intake were investigated. The present study aimed to investigate the anti-obesity potential of B. serrata extract. The effects on lipase activity and acute food intake were investigated. Body weight changes, biochemical and histopathological markers were demonstrated in rats fed a high-fat diet.

RESULTS

Boswellia serrata extract inhibited alterations in pancreatic lipase activity, but orlistat was more efficacious. B. serrata and ephidrene, but not orlistat, significantly suppressed cumulative food intake in mice. In obese rats, B. serrata or orlistat significantly decreased weight gain and weight of visceral white adipose tissue. B. serrata-treated animals exhibited a significant reduction in serum glucose, TC, TG, LDL-C, FFA, IL-1β, TNF-α, insulin and leptin levels of obese rat groups while HDL-C and adiponectin levels were significantly increased by orlistat or B. serrata extract. Histopathological examination of the liver revealed that B. serrata was more effective than orlistat in alleviating steatosis and adipocyte hypertrophy shown in obese control rats.

CONCLUSIONS

Boswellia serrata is as effective as orlistat in preventing obesity, hyperlipidemia, steatosis and insulin resistance. These actions may be mediated by suppression of food intake and decrease levels of TNF-α, IL-1β and leptin resistance along with increasing adiponectin.