A Hypercaloric pellet-diet cycle induces obesity and co-morbidities in wistar rats

Chronic hyperpalatable diet induces impairment of hippocampal-dependent memories and alters glutamatergic and fractalkine axis signaling

Chronic consumption of hyperpalatable and hypercaloric foods has been pointed out as a factor associated with cognitive decline and memory impairment in obesity. In this context, the integration between peripheral and central inflammation may play a significant role in the negative effects of an obesogenic environment on memory. However, little is known about how obesity-related peripheral inflammation affects specific neurotransmission systems involved with memory regulation. Here, we test the hypothesis that chronic exposure to a highly palatable diet may cause neuroinflammation, glutamatergic dysfunction, and memory impairment. For that, we exposed C57BL/6J mice to a high sugar and butter diet (HSB) for 12 weeks, and we investigated its effects on behavior, glial reactivity, blood-brain barrier permeability, pro-inflammatory features, glutamatergic alterations, plasticity, and fractalkine-CX3CR1 axis. Our results revealed that HSB diet induced a decrease in memory reconsolidation and extinction, as well as an increase in hippocampal glutamate levels. Although our data indicated a peripheral pro-inflammatory profile, we did not observe hippocampal neuroinflammatory features. Furthermore, we also observed that the HSB diet increased hippocampal fractalkine levels, a key chemokine associated with neuroprotection and inflammatory regulation. Then, we hypothesized that the elevation on glutamate levels may saturate synaptic communication, partially limiting plasticity, whereas fractalkine levels increase as a strategy to decrease glutamatergic damage.

Impact of Normal and Overweight Pregnancy in GLUT4 and Glucose-Dependent Vascular Contractility

INTRODUCTION

Obesity during pregnancy can contribute to hypertensive complications through changes in glucose utilization. We investigated the impact of vascular glucose uptake, GLUT4 density, and endothelium on agonist-induced vasoconstriction in the aortas of overweight pregnant rats.

METHODS

Isolated aortic rings with or without endothelium from pregnant or nonpregnant rats fed a standard (SD) or hypercaloric diet (HD) were contracted with phenylephrine or serotonin (10-9 to 10-4M) using standard (11 mm) or without (0 mm) glucose Krebs solution. GLUT4 density in the aortas was measured using the en face method.

RESULTS

Aortas from overweight pregnant animals (PHD) showed increased Phe-induced vasoconstriction (p < 0.05 vs. pregnant standard diet [PSD]), which was endothelium-independent. The contraction decreased significantly in the absence of glucose. In contrast, vessels from pregnant SD rats maintained their contraction in glucose-free Krebs solution. 5-HT increases PHD aortic contraction only in the absence of glucose. The fetal aortas from PHD mothers showed blunted vasoconstriction. Overweight significantly reduced GLUT4 expression in maternal and fetal aortas (p < 0.05 vs. PSD).

CONCLUSIONS

Aortic contractility is independent of glucose uptake during healthy pregnancy. In contrast, overweight pregnancy increases contractility. This increase depends directly on smooth muscle glucose uptake and inversely on GLUT-4 density. The increased contraction observed in the vasculature of overweight mothers was inverted in the fetal aortas.

Hypoglycemic and Hypotensive Effects of Calycotome villosa Subsp. intermedia Seeds in Meriones shawi Rats: In Vivo, Ex Vivo, and In Vitro Investigations

Calycotome villosa subsp. intermedia is used in traditional medicine for the prevention and self-treatment of a variety of illnesses, including diabetes mellitus, obesity, and hypertension. The present study aims to investigate the in vivo, ex vivo, and in vitro hypoglycemic and hypotensive effects of the lyophilized aqueous extract of Calycotome villosa subsp. intermedia seeds (CV) on Meriones shawi submitted to hypercaloric diet and physical inactivity (HCD/PI) for 12 weeks. This diet induces a type 2 diabetes/metabolic syndrome phenotype with hypertension. Furthermore, HCD/PI decreased aorta contraction due to noradrenaline, enhanced L-arginine, and depressed insulin-evoked relaxation, while the relaxing effects of the NO donor SNAP and of diazoxide were unchanged. In vivo experiments showed that the oral administration of the CV extract (50 mg/kg b.wt) for 3 consecutive weeks significantly attenuated the development of type 2 diabetes, obesity, dyslipidemia, and hypertension. These effects may involve the improvement of lipid metabolism, insulin sensitivity, systolic arterial pressure, and urine output. Additionally, ex vivo and in vitro investigations revealed that CV treatment improved vascular contraction to noradrenaline, induced a slight aorta relaxation in response to carbachol, increased the vasorelaxation effect evoked by insulin, and depressed the L-arginine evoked relaxation. However, CV did not change the endothelium-independent vasorelaxation response evoked by SNAP or diazoxide. Hence, the present study provides useful information and supports the traditional use of CV in the prevention and self-treatment of numerous ailments. Overall, it can be concluded that Calycotome villosa subsp. intermedia seed extracts might be useful in the management of type 2 diabetes and hypertension.

Metabolic dysfunctions promoted by AIN-93G standard diet compared with three obesity-inducing diets in C57BL/6J mice

Researchers from different fields have studied the causes of obesity and associated comorbidities, proposing ways to prevent and treat this condition by using a common animal model of obesity to create a profound energy imbalance in young adult rodents. However, to confirm the harmful effects of consuming a high-fat and hypercaloric diet, it is common to include normolipidic and normocaloric control groups in the experimental protocols. This study compared the effect of three experimental diets described in the literature - namely, a high-fat diet, a high-fat and high-sucrose diet, and a high-fat and high-fructose diet - to induce obesity in C57BL/6 J mice with the standard AIN-93G diet as a control. We hypothesize that the AIN diet formulation is not a good control in this type of experiment because this diet promotes weight gain and metabolic dysfunctions similar to the hypercaloric diet. The metabolic data of animals fed the AIN-93G diet were similar to those of the high-calorie groups (development of steatosis and hyperlipidemia). However, it is important to emphasize that the group fed a high-fat diet had a higher percentage of total fat (p = 0.0002) and abdominal fat (p = 0.013) compared to the other groups. Also, the high-fat group responded poorly to glucose and insulin tolerance tests, showing a picture of insulin resistance. As expected, the intake of the AIN-93G diet promotes metabolic alterations in the animals like the high-fat formulations. Therefore, although this diet continues to be used as the gold standard for growth and maintenance, it warrants a reassessment of its composition to minimize the metabolic changes observed in this study, thus updating its fitness as a normocaloric model of a standard rodent diet.

High-fat diet during sexual maturation induces hyperplastic differentiation of rat prostate and higher expression of AR45 isoform and ERα

We examined the consequences of high-fat diet (HFD) on prostate histophysiology in two periods along sexual maturation of rats and the impact on the gland in adulthood. After weaning, male Wistar rats were fed a balanced diet (4 % fat-C3, C6, C9) or a HFD (20 % fat- HF3, HF6, HF9) for 3, 6 or 9 weeks. Fat deposit weights, blood glucose and levels of serum testosterone and estrogen were measured. Prostate was evaluated for histology, proliferative and apoptotic cell index, and for the expression of androgen (AR), estrogen receptors type α (ERα) and aromatase. HFD did not affect estrogen levels and elevated serum testosterone only in HF9. HFD reduced prostate weight in HF6 and increased it in adulthood (HF9) but relative prostate weight was unchanged among groups. Cell proliferation, height and density were higher in epithelium of all HFD-groups, compared to controls, featuring the epithelial hyperplasia. Epithelial apoptosis was lower in HF9. HF3 and HF9 exhibited higher expressions of ERα, indicating that HFD triggers a new activation of ERα expression in the acinar epithelium. The content of prostatic aromatase was also elevated in HF9. Increased numbers of AR-positive cells were observed in all HFD groups, and western blotting analysis showed an increase in the truncated form of 45 kDa (AR45) and a reduction in the expression of 110 kDa-AR for HF3 and HF9. In conclusion, excessive dietary fats during sexual maturation of rats led to developmental programming of the prostate, inducing a hyperplastic status with perturbations in AR isoforms expression and reactivation of ERα in adulthood, whose implications for posterior prostatic health could be detrimental.

Supplementation with Spirulina platensis Prevents Damage to Rat Erections in a Model of Erectile Dysfunction Promoted by Hypercaloric Diet-Induced Obesity

Erectile dysfunction (ED) is the inability to achieve and/or maintain a penile erection sufficient for sexual satisfaction. Currently, many patients do not respond to the pharmacotherapy. The effects of a supplementation with Spirulina platensis, were evaluated in a model of ED induced by hypercaloric diet consumption. Wistar rats were divided into groups fed with standard diet (SD) or hypercaloric diet (HD) and supplemented with this alga at doses of 25, 50 or 100 mg/kg. Experimental adiposity parameters and erectile function were analyzed. In SD groups, Spirulina platensis reduced food intake, final body mass and adiposity index, and increased the total antioxidant capacity (TAC) of adipose tissue. However, no change was observed in erectile function. In the HD group, without Spirulina supplementation, a decrease in food intake was observed, in addition to an increase of final body mass, weight gain, adipose reserves, and adiposity index. Additionally, reduction in the number and increase in the latency of penile erection and adipose malondialdehyde levels, as well as a reduction in TCA was noted. Furthermore, cavernous contractility was increased, and the relaxing response was decreased. Interestingly, these deleterious effects were prevented by the algae at doses of 25, 50 and/or 100 mg/kg. Therefore, the supplementation with S. platensis prevents damages associated to a hypercaloric diet consumption and emerges as an adjuvant the prevention of ED.

Effect of Encapsulated Ferrous Sulphate Fortified Salt on Hemoglobin Levels in Anemic Rats

(1) Background: Iron deficiency anemia is a significant nutritional problem all over the world. Salt formulations supplemented with encapsulated iron and iodine (double-fortified) were tested for their efficacy in managing iron deficiency anemia. In this study, we have checked the effect of these double-fortified salt formulations (iron and iodine) on hemoglobin (Hb) levels in anemic Wistar male rats. (2) Methods: The study was divided into two phases, viz., the development of anemia in the first phase and then the random division of anemic rats into five groups (Groups A to E). These rats were fed with three different salt formulations (Groups A to C); Group D was continued on a low iron diet, and Group E was on a normal pellet diet over a period of 84 days. The level of Hb was tested in each group. (3) Results: The rats in Groups A, B, C, and E recovered from anemia significantly, with higher Hb levels. On day 84, however, the Hb level in Group D continued to decrease. The bodyweight of the rats was not affected in any way. In all of the groups, histopathology examinations in various organs revealed no significant changes. (4) Conclusions: All of the three different salt formulations showed significant recovery in the anemic rats as compared to the rats fed with a normal pelleted diet.

Antidiabetic Properties and Toxicological Assessment of Antidesma celebicum Miq: Ethanolic Leaves Extract in Sprague-Dawley Rats

Antidesma is a genus of plants, and its several species are known to have antidiabetic properties. Leaves of Kayu Tuah (Antidesma celebicum Miq) have been proven to have the best α-glucosidase inhibition ability compared to other species in the Antidesma genus, as evidenced by the in vitro α-glucosidase inhibition test. However, no scientific studies have reported its antidiabetic properties and toxicity in vivo. Therefore, this research managed to verify the antidiabetic features and safety of ethanolic extract of A. celebicum leaves (EEAC) in Sprague-Dawley rats. Male rats (170-280 g) were induced diabetic with streptozotocin (35 mg/kg BW) and fed a high-fat diet comprising 24% fat, whereas control group rats were given a standard diet. Rats were treated with EEAC at 200 and 400 mg/kg BW doses for 28-days and 60 mg/kg BW acarbose for the control group. Determination of antidiabetic properties was done by analyzing lipid profiles as well as fasting blood glucose. After confirming the antidiabetic properties of EEAC, the toxicological assessment was determined using the fixed-dose method. General behavior changes, appearance, signs of toxicity, mortality, and body weight of animals were marked down during the observation period. When the treatment period ended, hematological, biochemical, and histological examinations of liver, kidneys, and heart sections were performed. The results confirmed that EEAC reduced fasting blood glucose levels and stepped forward lipid profiles of rats. Also, all animals survived, and no obvious destructive outcomes were noticeable during the study. As EEAC has promising results toward hyperglycemia and hyperlipidemia and has been proven safe through toxicity tests, it can be concluded that EEAC has good potential to be further developed into antidiabetic drugs.

Polar fraction from Parkinsonia aculeata aerial parts extract improves imbalanced metabolic profile and reduces proinflammatory interleukin levels in white adipose tissue in obese rats induced by western diet

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinsonia aculeata L. (Cesalpineaceae) is a medium tree found in the Xingó region (semi-arid area) in Northeast of Brazil, recognised by local population as an antidiabetic agent. According information from local community, the commonly traditional preparation is prepared as an infusion of the aerial part of the plant and consumed over the day to manage diabetes-related complications. Previous studies have described Parkinsonia aculeate as a product with both hypoglycemic and hypotriglyceridemic effects.

AIM OF THE STUDY

The objective of this study was to evaluate the effects of polar fraction obtained from the hydroethanolic extract of Parkinsonia aculeata (PfrHEPA) on the lipid profile of animals that consumed a westernized diet.

MATERIALS AND METHODS

Thirty-six Wistar rats (45-55 g) were fed either with standard control(C) or westernized diet(W) for 120 days. The food intake, body weight evolution and body size were also analyzed. From 120 to 150 days, they were orally treated according to their group with vehicle (distillated water, 10 mL/kg), PfrHEPA at three doses (35, 70 and 140 mg/kg/day) or Gemfibrozil (140 mg/kg/day) for 30 days.

RESULTS

The animals fed with westernized diet showed dyslipidemia when compared to animals receiving a standard diet. Treatment with PfrHEPA (140 mg/kg), even with the continued consumption of westernized diet by animals (from 120 to 150 days) promoted a significant reduction in total cholesterol, LDL and triglyceride levels, in relation to untreated W group. PfrHEPA 140 mg/kg reduced the key serum lipids and glycaemia as well as inflammatory cytokines known as important risk factors of cardiovascular diseases.

CONCLUSIONS

The observed evidence may contribute to the control of metabolic parameters as dyslipidemia corroborating the ethnopharmacological information concerning the antihyperlipidemic and hypoglycemic activities of P. aculeata.

Spirulina platensis Consumption Prevents Obesity and Improves the Deleterious Effects on Intestinal Reactivity in Rats Fed a Hypercaloric Diet

The consumption of hypercaloric diets is related to the development of obesity, favoring the etiology of gastrointestinal disorders. In this context, Spirulina platensis (SP), some blue-green algae with antioxidant action, appears as a potential therapeutic alternative to prevent obesity and associated intestinal disorders. Thus, the present study is aimed at evaluating the deleterious effects of the hypercaloric diet on the contractile and relaxing reactivity of the ileum of rats, as well as the possible preventive mechanisms of dietary supplementation with SP. Wistar rats were divided into three groups: fed a standard diet (SD), a hypercaloric diet (HCD), and/or supplemented with 25 mg/kg SP (HCD + SP25) for 8 weeks. The hypercaloric diet was effective in promoting obesity in rats, as well as decreasing potency and ileal relaxing and contractile efficacy. In contrast, dietary supplementation with SP was able to prevent some of the parameters of experimental obesity. In addition, SP prevented the reduction of intestinal reactivity, possibly due to a positive modulation of voltage-gated calcium channels (CaV) and negative regulation of muscarinic receptors (M3). Thus, food supplementation with Spirulina platensis becomes a promising alternative in the prevention of gastrointestinal diseases induced and/or aggravated by obesity.

Caloric restriction prevents alveolar bone loss in the experimental periodontitis in obese rats

AIMS

It has been shown that periodontitis, can be modified by systemic changes, including behavioral factors, such as diet. Caloric restriction is one of the dietary therapeutic strategies indicated for obesity. It is associated with several benefits, among them, modulation of the inflammatory response. The aim of this study was to verify whether caloric restriction in obese rats changes the progression of experimental ligature-induced periodontitis.

MATERIALS AND METHODS

Forty-eight Wistar rats were used for 24 weeks and initially fed with cafeteria diet during 12 weeks. The animals were divided into four groups according to the caloric restriction and experimental periodontitis. The cotton thread was placed around the mandibular first molars, for 15 days, before the end of the experiment. Rats submitted to caloric restriction received, from the 13th week of the experimental protocol, 70% of the food intake compared to the ad libitum animals of other study of the our research group. Alveolar bone loss was assessed using macroscopic morphometric analysis. Analyzes of clinical periodontal measures, biometrics, serum biomarkers and biochemical parameters were performed.

KEY FINDINGS

Caloric restriction decreased the alveolar bone loss in the periodontitis group when compared to the group that received a cafeteria diet with periodontitis. Moreover, the results demonstrate the improvement in the glycemic profile, without prejudice to bone tissue biomarkers.

SIGNIFICANCE

Based on the results, caloric restriction reduces the progression of alveolar bone loss in rats with experimental periodontitis, in addition to presenting benefits in biometric data, decreasing both glycemic profile and clinical periodontal measures.

Melatonin ameliorates degenerative alterations caused by age in the rat prostate and mitigates high-fat diet damages

Imbalance of sexual steroids milieu and oxidative stress are often observed during aging and correlated to prostate disorders. Likewise, high-fat intake has been related to prostate damage and tumor development. Melatonin (MLT) is an antioxidant whose secretion decreases in elderly and is also suggested to protect the gland. This study evaluated the impact of a long-term high-fat diet during aging on prostate morphology and antioxidant system of rats and tested the effects of MLT supplementation under these conditions. Male rats were assigned into four groups: control, treated with MLT, high-fat diet and high-fat diet treated with MLT. The high-fat diet was provided from the 24th week of age, MLT from the 48th (100 μg/kg/day) and rats were euthanized at the 62nd week. The high-fat diet increased body weight, retroperitoneal fatness, glycaemia, and circulating estrogen levels. It aggravated the aging effects, leading to epithelial atrophy (∼32% reduction of epithelial height) and collagen fibers increase (83%). MLT alone did not alter biometric and physiological parameters, except for the prostate weight decrease, whereas it alleviated biometric as well as ameliorated acinar atrophy induced by high-lipid intake. Systemic oxidative stress increased, and prostatic glutathione peroxidase activity decreased fivefold with the high-fat diet despite the indole. Regardless of the diet, MLT triggered epithelial desquamation, reduced androgen receptor-positive cells, increased smooth muscle layer thickness (12%), decreased at least 50% corpora amylacea formation, and stimulated prostatic gluthatione-S-transferase activity. In conclusion, MLT partially recovered prostate damage induced by aging and the long-term high-fat diet and ameliorated degenerative prostate alterations.

Hippocampal electrophysiological changes during the elicited metabolic syndrome in Wistar rats

The Metabolic Syndrome (MS) is a set of alterations that increase the risk of developing type 2 diabetes mellitus (DM2). There is evidence that obesity and the development of metabolic syndrome lead to alterations in cognitive processes. In this work it was proposed to determine if generating the metabolic syndrome produces changes in the electric unitary spontaneous activity in the hippocampus as a possible sustain of the learning alterations. In Wistar rat with a hypercaloric diet, metabolic syndrome was provoked, and this was confirmed with the determination of body and metabolic parameters as a measure of intraperitoneal fat, glucose, triglycerides, and cholesterol. Electrophysiological records were made in the hippocampus and it was determined that rats treated with a hypercaloric diet show a significant decrease in such activity. Thus, it is shown that rats that were caused metabolic syndrome, alter their hippocampal electrophysiological activity.

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In Wistar rat a hypercaloric diet produces metabolic syndrome.

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Metabolic syndrome causes decreased hippocampal activity in Wistar rat.

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Metabolic syndrome produces physiological and metabolic alterations in Wistar rat.

Expression profiling and analysis of some miRNAs in subcutaneous white adipose tissue during development of obesity

Background

MicroRNAs are emerging as new mediators in the regulation of adipocyte physiology and have been approved to play a role in obesity. Despite several studies have focused on microRNA expression profiles and functions in different metabolic tissues, little is known about their response to nutritional interventions in white adipose tissue during obesity stages, and whether they differ in this response to weight-reduction strategy is poorly understood. Our objectives were to study the dysregulation of some miRNAs in subcutaneous inguinal white adipose tissue during weight change, expansion/reduction; in response to both a high-fat diet and switching to a normal diet feeding, and to evaluate them as potential biomarkers and therapeutic targets for early obesity management

Method

A hundred 6-week-old male Wister rats were randomly divided into a normal diet group (N.D), a high-fat diet group (H.F.D), and a switched to a normal diet group (H.F.D/N.D). At the beginning and at intervals 2 weeks, serum lipid, hormone levels, total body fat mass, and inguinal subcutaneous white adipose tissue mass (WAT) measurements were recorded using dual-energy X-ray absorptiometry (DEXA). The expression levels of microRNAs were evaluated using real-time PCR.

Results

Significant alterations were observed in serum glucose, lipid profile, and adipokine hormones during the early stages of obesity development. Alteration in rno-mir 30a-5p, rno-mir 133a-5p, and rno-mir 107-5p expression levels were observed at more than one time point. While rno-let-7a-5p, rno-mir 193a-5p, and rno-mir125a-5p were downregulated and rno-mir130a-5p was upregulated at all time points within 2 to 4 weeks in response to H.F.D feeding for 10 weeks. The impact of switching to normal diet has a reversed effect on lipid profile, adipokine hormone levels, and some miRNAs. The bioinformatics results have identified a novel and important pathway related to inflammatory signalling.

Conclusion

Our research demonstrated significant alterations in some adipocyte-expressed miRNAs after a short time of high caloric diet consumption. This provides further evidence of the significant role of nutrition as an epigenetic factor in regulation of lipid and glucose metabolism genes by modulating of related key miRNAs. Therefore, we suggest that miRNAs could be used as biomarkers for adiposity during diet-induced obesity. Perhaps limitation in calories intake is a way to manipulate obesity and associated metabolic disorders. Further studies are needed to fully elucidate the role of microRNAs in the development of obesity

Rodent models of obesity

Obese or overweight people exceed one-third of the global population and obesity along with diabetes mellitus consist basic components of metabolic syndrome, both of which are known cardio-cerebrovascular risk factors with detrimental consequences. These data signify the pandemic character of obesity and the necessity for effective treatments. Substantial advances have been accomplished in preclinical research of obesity by using animal models, which mimic the human disease. In particular, rodent models have been widely used for many decades with success for the elucidation of the pathophysiology of obesity, since they share physiological and genetic components with humans and appear advantageous in their husbandry. The most representative rodents include the laboratory mouse and rat. Within this review, we attempted to consolidate the most widely used mice and rat models of obesity and highlight their strengths as well as weaknesses in a critical way. Our aim was to bridge the gap between laboratory facilities and patient's bed and help the researcher find the appropriate animal model for his/her obesity research. This tactful selection of the appropriate model of obesity may offer more translational derived results. In this regard, we included, the main diet induced models, the chemical/mechanical ones, as well as a selection of monogenic or polygenic models.

Dietary supplementation with Camu-Camu versus sleeve gastrectomy in Wistar rats weight control

OBJECTIVE

to compare the effects of the hydroalcoholic extract from the peel of Camu-Camu, a fruit plant belonging to the Myrtaceae family, widely distributed in the Amazon basin, with those of sleeve gastrectomy, on the weight and glycemia of Wistar rats.

METHODS

twenty-four Wistar rats underwent obesity induction through a hyperlipid diet for eight weeks (fat period), and were randomized into three groups: Control Group (CG), Camu-Camu Group (CCG) and Bariatric Surgery Group (BSG). After this period, all animals returned to a normal diet and the intervention period began: CG did not undergo any intervention beyond diet change; CCG animals underwent gavage procedure for administration of Camu-Camu hydroalcoholic extract, 1g/kg/day, for four weeks; and the BSG was submitted to the surgical procedure of sleeve gastrectomy. We followed all animals for four weeks.

RESULTS

there was only one loss in BSG due to a gastric fistula. We observed significant variations in the animals' mean weight: the CG evolved with weight gain even after the withdraw of the hypercaloric diet, while the other two groups presented weight reduction. BSG presented a significant reduction of weight and BMI (p<0.05); CCG achieved a significant reduction only of the BMI (p<0.05). There were no statistically significant changes in the glycemic levels.

CONCLUSION

in spite of reducing weight, the crude hydroalcoholic extract of the Camu-Camu peel was not able to be as efficient as sleeve gastrectomy in the control of body weight in Wistar rats.

Cardiac function and intracellular Ca2+ handling proteins are not impaired by high-saturated-fat diet-induced obesity

Obesity is often associated with changes in cardiac function; however, the mechanisms responsible for functional abnormalities have not yet been fully clarified. Considering the lack of information regarding high-saturated-fat diet-induced obesity, heart function, and the proteins involved in myocardial calcium (Ca²⁺) handling, the aim of this study was to test the hypothesis that this dietary model of obesity leads to cardiac dysfunction resulting from alterations in the regulatory proteins of intracellular Ca²⁺ homeostasis. Male Wistar rats were distributed into two groups: control (C, n=18; standard diet) and obese (Ob, n=19; high-saturated-fat diet), which were fed for 33 weeks. Cardiac structure and function were evaluated using echocardiographic and isolated papillary muscle analyses. Myocardial protein expressions of sarcoplasmic reticulum Ca²⁺-ATPase, phospholamban (PLB), PLB serine-16 phosphorylation, PLB threonine-17 phosphorylation, ryanodine receptor, calsequestrin, Na⁺/Ca²⁺ exchanger, and L-type Ca²⁺ channel were assessed by western blot. Obese rats presented 104% increase in the adiposity index (C: 4.5±1.4 vs Ob: 9.2±1.5%) and obesity-related comorbidities compared to control rats. The left atrium diameter (C: 5.0±0.4 vs Ob: 5.5±0.5 mm) and posterior wall shortening velocity (C: 36.7±3.4 vs Ob: 41.8±3.8 mm/s) were higher in the obese group than in the control. The papillary muscle function was similar between the groups at baseline and after inotropic and lusitropic maneuvers. Obesity did not lead to changes in myocardial Ca²⁺ handling proteins expression. In conclusion, the hypothesis was not confirmed, since the high-saturated-fat diet-induced obese rats did not present cardiac dysfunction or impaired intracellular Ca²⁺ handling proteins.

Effects of AT1 receptor antagonism on interstitial and ultrastructural remodeling of heart in response to a hypercaloric diet

Palatable hypercaloric feeding has been associated with angiotensin-II type 1 receptor (AT1R) stimulation and cardiac remodeling. This study analyzed whether AT1R antagonism attenuates cardiac remodeling in rats subjected to a palatable hypercaloric diet. Male Wistar-Kyoto rats were subjected to a commercial standard rat chow (CD) or a palatable hypercaloric diet (HD) for 35 weeks and then allocated into four groups: CD, CL, HD, and HL; L groups received losartan in drinking water (30 mg/kg/day) for 5 weeks. Body weight, adiposity, and glycemia were evaluated. The cardiovascular study included echocardiography, and myocardial morphometric and ultrastructural evaluation. Myocardial collagen isoforms Type I and III were analyzed by Western blot. Both HD and HL had higher adiposity than their respective controls. Cardiomyocyte cross-sectional-area (CD 285 ± 49; HD 344 ± 91; CL 327 ± 49; HL 303 ± 49 μm2 ) and interstitial collagen fractional area were significantly higher in HD than CD and unchanged by losartan. HD showed marked ultrastructural alterations such as myofilament loss, and severe mitochondrial swelling. CL presented higher Type I collagen expression when compared to CD and HL groups. The ultrastructural changes and type I collagen expression were attenuated by losartan in HL. Losartan attenuates systolic dysfunction and ultrastructural abnormalities without changing myocardial interstitial remodeling in rats subjected to a palatable hypercaloric diet.

Modelos animais na síndrome metabólica

RESUMO O conhecimento sobre modelos animais para estudo metabólico representa a base da pesquisa nessa área. Este trabalho tem por objetivo revisar os principais modelos animais a serem utilizados no estudo da obesidade e da síndrome metabólica. Para isso, pesquisa no banco de dados Pubmed foi realizada usando as palavras-chave “animal models”, “obesity”, "metabolic syndrome”, e “bariatric surgery”. Várias espécies de animais podem ser usadas para o estudo de distúrbios metabólicos, no entanto, os roedores, tanto modelos monogênicos quanto modelos de obesidade induzida por dieta (DIO), são os animais mais utilizados nessa área. Animais monogênicos são a melhor escolha se apenas um aspecto estiver sendo avaliado. Animais DIO tendem a demonstrar melhor a interação entre doença, ambiente e gene. No entanto, eles ainda não são totalmente eficazes para a compreensão de todos os mecanismos dessa doença.

Investigating of Moringa Oleifera Role on Gut Microbiota Composition and Inflammation Associated with Obesity Following High Fat Diet Feeding

AIM

The alteration in the gut microbial community has been regarded as one of the main factors related to obesity and metabolic disorders. To date, little is known about Moringa oleifera as a nutritional intervention to modulate the microbiota imbalance associated with obesity. Therefore we aim to explore the role of aqueous Moringa oleiferous leaf extract on Lactobacilli and Bifidobacteria in high-fat diet-induced obesity and to investigate whether any restoration in the number of caecal Lactobacilli and Bifidobacteria could modulate obesity-induced inflammation.

METHODS

Young Swiss albino mice were divided into three groups according to their diet. Two of them were fed on either high fat diet or high fat diet+aqueous extract of Moringa oleifera leaf, while the third group was fed on the control diet. Bacterial DNAs were isolated from the mice digesta samples for bacteria level estimation using Quantitative real-time polymerase chain reaction along with serum interleukin-6 and lipid profile.

RESULTS

Compared to the normal control mice, high-fat diet feeding mice showed significantly reduced intestinal levels of Bifidobacteria, and increased body weight, interleukin 6, and levels of Lactobacilli. Upon treatment with Moringa oleifera, body weight, interleukin 6, and both bacteria levels were significantly restored.

CONCLUSIONS

Our findings suggest that Moringa oliefera aqueous leaf extract may contribute towards the pathophysiological regulation of weight gain, inflammation associated with high-fat-induced-obesity through gut bacteria modulation.

Differential Effects of High Sugar, High Lard or a Combination of Both on Nutritional, Hormonal and Cardiovascular Metabolic Profiles of Rodents

BACKGROUND

Dietary interventions in rodents can induce an excess of adipose tissue and metabolic disorders that resemble human obesity. Nevertheless, these approaches are not standardized, and the phenotypes may vary distinctly among studies. The aim of this study was to investigate the effects of different dietary interventions on nutritional, metabolic, biochemical, hormonal, and cardiovascular profiles, as well as to add to development and characterization of an experimental model of obesity.

METHODS

Male Wistar rats were randomized into four groups: control diet (C), high-sugar (HS), high-fat (HF), or high-sugar and high-fat (HFHS). Weekly measurements of body weight, adiposity, area under the curve (AUC) for glucose, blood pressure (BP) and serum triglycerides, total cholesterol level, and leptin were performed.

RESULTS

HF and HFHS models were led to obesity by increases in adipose tissue deposition and the adiposity index. All hypercaloric diets presented systolic BP increases. In addition, the AUC for glucose was greater in HF and HFHS than in C, and only the HF group presented hyperleptinemia.

CONCLUSIONS

HF and HFHS diet approaches promote obesity and comorbidities, and thus represent a useful tool for studying human obesity-related disorders. By contrast, the HS model did not prove to be a good model of obesity.

Benefits of Fish Oil Consumption over Other Sources of Lipids on Metabolic Parameters in Obese Rats

This study evaluated the effect of the consumption of different levels and sources of lipids on metabolic parameters of Wistar rats. Animals were fed with high-fat diet (HFD) containing 20% of lard for 12 weeks to cause metabolic obesity. Subsequently, the animals were divided into six groups and were fed diets with lipid concentrations of 5% or 20% of lard (LD), soybean oil (SO) or fish oil (FO), for 4 weeks. Data were submitted to analysis of variance (two-way) followed by Tukey post hoc test (p < 0.05). The groups that consumed FO showed less weight gain and lower serum levels of triacylglycerol (TAG), total cholesterol and fractions, aspartate aminotransferase (AST) activity, atherogenic index, less amount of fat in the carcass, decreased Lee index and lower total leukocyte counting (p < 0.05). These same parameters were higher in LD treatment (p < 0.05). In the concentration of 20%, carcass fat content, blood glucose levels, as well as alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) decreased in FO groups (p < 0.05). The SO group had intermediate results regarding the other two treatments (FO and LD). We concluded that fish oil intake was able to modulate positively the metabolic changes resulting from HFD.

Saturated high-fat diet-induced obesity increases adenylate cyclase of myocardial β-adrenergic system and does not compromise cardiac function

Obesity is a worldwide pandemic associated with high incidence of cardiovascular disease. The mechanisms by which the obesity leads cardiac dysfunction are not fully elucidated and few studies have evaluated the relationship between obesity and proteins involved in myocardial β‐adrenergic (βA) system. The purpose of this study was to evaluate the cardiac function and βA pathway components in myocardium of obese rats. Male Wistar rats were distributed into two groups: control (n = 17; standard diet) and obese (n = 17; saturated high‐fat diet) fed for 33 weeks. Nutritional profile and comorbidities were assessed. Cardiac structure and function was evaluated by macroscopic postmortem, echocardiographic and isolated papillary muscle analyzes. Myocardial protein expression of β₁‐ and β₂‐adrenergic receptors, Gαs protein, adenylate cyclase (AC) and protein kinase A (PKA) was performed by Western blot. Cardiac cyclic adenosine monophosphate (cAMP) levels and PKA activity were assessed by ELISA. Obese rats showed increased adiposity index (P < 0.001) and several comorbidities as hypertension, glucose intolerance, insulin resistance, and dyslipidemia compared with control rats. Echocardiographic assessment revealed increased left atrium diameter (C: 4.98 ± 0.38 vs. Ob: 5.47 ± 0.53, P = 0.024) and posterior wall shortening velocity (C: 37.1 ± 3.6 vs. Ob: 41.8 ± 3.8, P = 0.007) in obese group. Papillary muscle evaluation indicated that baseline data and myocardial responsiveness to isoproterenol stimulation were similar between the groups. Protein expression of myocardial AC was higher in obese group than in the control (C: 1.00 ± 0.21 vs. Ob: 1.25 ± 0.10, P = 0.025), whereas the other components were unchanged. These results suggest that saturated high‐fat diet‐induced obesity was not effective in triggering cardiac dysfunction and impair the beta‐adrenergic signaling.

Hypercaloric Diet Establishes Erectile Dysfunction in Rat: Mechanisms Underlying the Endothelial Damage

Obesity is characterized by an excessive increase in body mass, leading to endothelial damage that may favor the development of erectile dysfunction (ED). ED is defined as the inability to achieve or maintain a penile erection long enough to have a sexual intercourse. In this context, different ED models were developed, however the high price of special animals or the long period to establish the disease has limited studies in this field. Therefore, this study proposed to establish and characterize a novel model of ED in rats associated to a hypercaloric diet consumption. Animals were randomly divided into control group (CG), which received a standard diet, and obese group (OG), fed with a hypercaloric diet during 8 weeks. Rat's erectile function was evaluated in vivo and in vitro. Food and caloric intake of OG were reduced compared to CG, due to an increased diet energy efficiency. However, OG presented an increased body mass, inguinal, retroperitoneal and epididymal adipose tissues, as well as body adiposity index at the end of experimental protocol. In erectile function analysis, there was a decrease in the number and the latency of penile erections in OG. Additionally, the contractile reactivity of corpus cavernosum was increased in OG, favoring penile detumescence and related to a reduced nitric oxide bioavailability and an increased in contractile prostaglandins levels as a consequence of endothelial damage. Moreover, the endothelium-relaxation reactivity of corpus cavernosum was attenuated in OG associated to the oxidative stress. Thus, it was provided a model for advances in sexual dysfunction field and drug discovery for ED treatment.

Metabolic syndrome and inflammation in adipose tissue occur at different times in animals submitted to a high-sugar/fat diet

Obesity is associated with low-grade inflammation, triggered in adipose tissue, which may occur due to an excess of SFA from the diet that can be recognised by Toll-like receptor-4. This condition is involved in the development of components of the metabolic syndrome associated with obesity, especially insulin resistance. The aim of the study was to evaluate the manifestation of the metabolic syndrome and adipose tissue inflammation as a function of the period of time in which rats were submitted to a high-sugar/fat diet (HSF). Male Wistar rats were divided into six groups to receive the control diet (C) or the HSF for 6, 12 or 24 weeks. HSF increased the adiposity index in all HSF groups compared with the C group. HSF was associated with higher plasma TAG, glucose, insulin and leptin levels. Homeostasis model assessment increased in HSF compared with C rats at 24 weeks. Both TNF-α and IL-6 were elevated in the epididymal adipose tissue of HSF rats at 24 weeks compared with HSF at 6 weeks and C at 24 weeks. Only the HSF group at 24 weeks showed increased expression of both Toll-like receptor-4 and NF-κB. More inflammatory cells were found in the HSF group at 24 weeks. We can conclude that the metabolic syndrome occurs independently of the inflammatory response in adipose tissue and that inflammation is associated with hypertrophy of adipocytes, which varies according to duration of exposure to the HSF.

Diet-induced obesity alters memory consolidation in female rats

Obesity is a multifactorial disease characterized by the abnormal or excessive fat accumulation, which is caused by an energy imbalance between consumed and expended calories. Obesity leads to an inflammatory response that may result in peripheral and central metabolic changes, including insulin and leptin resistance. Insulin and leptin resistance have been associated with metabolic and cognitive dysfunctions. Obesity and some neurodegenerative diseases that lead to dementia affect mainly women. However, the effects of diet-induced obesity on memory consolidation in female rats are poorly understood. Therefore, the aim of this study was to evaluate the effect of a hypercaloric diet on the object recognition memory of female rats and on possible related metabolic changes. The animals submitted to the hypercaloric diet presented a higher food intake in grams and in calories, resulting in increased weight gain and liposomatic index in comparison with the animals exposed to the control diet. These animals presented a memory deficit in the object recognition test and increased serum levels of glucose and leptin. However, no significant differences were found in the serum levels of insulin, TNF-α and IL-1β, in the index of insulin resistance (HOMA), in the hippocampal levels of insulin, TNF-α and IL-1β, as well as on Akt expression or activation in the hippocampus. Our findings indicate that adult female rats submitted to a hypercaloric diet present memory consolidation impairment, which could be associated with diet-induced weight gain and leptin resistance, even without the development of insulin resistance.

Anti-obesogenic and hypolipidemic effects of a glucagon-like peptide-1 receptor agonist derived from the saliva of the Gila monster

INTRODUCTION

Glucagon-like peptide-1 (GLP-1) receptor (R) agonists are a class of incretin mimetic drugs that have been used for the treatment of type 2 diabetes mellitus and also considered strong candidates for the treatment of obesity. The original prototypical drug in this class is the exenatide, a synthetic peptide with the same structure as the native molecule, exendin-4, found in the saliva of the Gila monster (Heloderma suspectum suspectum lizard).

OBJECTIVES

To identify and compare the anti-obesogenic, antidyslipidemic and antidiabetogenic effects of agonism in GLP-1R by exenatide on two distinct models of obesity: induced by hypothalamic injury (MSG) or high-calorie diet (DIO).

METHODS

To obtain MSG, neonatal rats were daily subcutaneously injected with 4 g monosodium glutamate/kg, for 10 consecutive days. To obtain DIO, 72-75 days old rats received hyperlipid food and 30% sucrose for drinking up to 142-145 days old. Untreated healthy rats with the same age were used as control. General biometric and metabolic parameters were measured.

RESULTS

MSG was characterized by decreased naso-anal length, food and fluid intake, plasma protein and glucose decay rate per minute after insulin administration (K_ITT), as well as increased Lee index (body mass^0.33/naso-anal length), mass of retroperitoneal and periepididymal fat pads, glycemia, triglycerides (TG), LDL and VLDL. Exenatide ameliorated K_ITT and food and fluid intake, and it also restored glycemia in MSG. DIO was characterized by glucose intolerance, increased body mass, Lee index, fluid intake, mass of retroperitoneal and periepididymal fat pads, glycemia, glycated hemoglobin (HbA1c), TG, VLDL and total cholesterol, as well as decreased food intake and K_ITT. Exenatide restored glycemia, HbA1c, TG, VLDL, total cholesterol and body mass, and it also ameliorated food and fluid intake, K_ITT and mass of retroperitoneal fat pad in DIO.

CONCLUSIONS

The hypothalamic injury and the high-calorie diet induce dyslipidemia and glycemic dysregulation in addition to obesity in rats. The usual therapeutic dose of exenatide in humans is antidiabetogenic in both these obesity models, but is anti-obesogenic and hypolipidemic only in diet-induced obesity. Agonists of GLP-1R are promising anti-obesogenic and antidyslipidemic drugs in the early stages of the obesity, in which the integrity of the nervous system was unaffected.

A high-fat diet fed during different periods of life impairs steroidogenesis of rat Leydig cells

This study evaluated the impact of a high-fat diet (HFD) during different stages of rat life, associated or not with maternal obesity, on the content of sex steroid hormones and morphophysiology of Leydig cells. The following periods of development were examined: gestation (O1), gestation and lactation (O2), from weaning to adulthood (O3), from lactation to adulthood (O4), gestation to adulthood (O5), and after sexual maturation (O6). The HFD contained 20% unsaturated fat, whereas the control diet had 4% fat. Maternal obesity was induced by feeding HFD 15 weeks before mating. All HFD groups presented increased body weight, hyperinsulinemia and reduced insulin sensitivity. Except for O1, all HFD groups exhibited a higher adiposity index, hyperleptinemia, reduced testosterone and estradiol testicular levels, and decreased testicular 17β-HSD enzyme . Morphometrical analyses indicated atrophy of Leydig cells in the O2 group. Myelin vesicles were observed in the mitochondrial matrix of Leydig cells in O3, O4, O5 and O6, and autophagosomes containing mitochondria were found in O5 and O6. In conclusion, HFD feeding, before or after sexual maturation, reduces the functional capacity of rat Leydig cells. Maternal obesity associated with HFD during pregnancy/lactation prejudices Leydig cell steroidogenesis and induces its atrophy in adulthood, even if it is replaced by a conventional diet at later stages of life. Regardless of the life period of exposure to HFD, deregulation of leptin is the main factor related to steroidogenic impairment of Leydig cells, and, in groups exposed for longer periods (O3, O4, O5 and O6), this is worsened by structural damage and mitochondrial degeneration of these cells.

A Trypsin Inhibitor from Tamarind Reduces Food Intake and Improves Inflammatory Status in Rats with Metabolic Syndrome Regardless of Weight Loss

Trypsin inhibitors are studied in a variety of models for their anti-obesity and anti-inflammatory bioactive properties. Our group has previously demonstrated the satietogenic effect of tamarind seed trypsin inhibitors (TTI) in eutrophic mouse models and anti-inflammatory effects of other trypsin inhibitors. In this study, we evaluated TTI effect upon satiety, biochemical and inflammatory parameters in an experimental model of metabolic syndrome (MetS). Three groups of n = 5 male Wistar rats with obesity-based MetS received for 10 days one of the following: (1) Cafeteria diet; (2) Cafeteria diet + TTI (25 mg/kg); and (3) Standard diet. TTI reduced food intake in animals with MetS. Nevertheless, weight gain was not different between studied groups. Dyslipidemia parameters were not different with the use of TTI, only the group receiving standard diet showed lower very low density lipoprotein (VLDL) and triglycerides (TG) (Kruskal-Wallis, p < 0.05). Interleukin-6 (IL-6) production did not differ between groups. Interestingly, tumor necrosis factor-alpha (TNF-α) was lower in animals receiving TTI. Our results corroborate the satietogenic effect of TTI in a MetS model. Furthermore, we showed that TTI added to a cafeteria diet may decrease inflammation regardless of weight loss. This puts TTI as a candidate for studies to test its effectiveness as an adjuvant in MetS treatment.

Differential ontogenetic exposure to obesogenic environment induces hyperproliferative status and nuclear receptors imbalance in the rat prostate at adulthood

BACKGROUND

Experimental data indicate that high-fat diet (HFD) may alter proliferative activity and prostate health. However, the consequences of HFD exposure during different periods of ontogenetic development on prostate histophysiology remain to be elucidated. Herein, we compare the influence of obesogenic environment (OE) due to maternal obesity and HFD at different periods of life on proliferative activity and nuclear receptors frequency in the rat ventral prostate and a possible relationship with metabolic and hormonal alterations.

METHODS

Male Wistar rats (19 weeks old), treated with balanced chow (Control group-C; 3% high-fat, 3.5 Kcal/g), were compared with those exposed to HFD (20% high-fat, 4.9 kcal/g) during gestation (G-maternal obesity), gestation and lactation (GL), from post-weaning to adulthood (WA), from lactation to adulthood (LA) and from gestation to adulthood (GA). After the experimental period, the ventral prostate lobes were removed and analyzed with different methods.

RESULTS

Metabolic data indicated that G and GL rats became insulin resistant and WA, LA, and GA became insulin resistant and obese. There was a strong inverse correlation between serum testosterone (∼133% lower) and leptin levels (∼467% higher) in WA, LA, and GA groups. Estrogen serum levels increased in GA, and insulin levels increased in all groups, especially in WA (64.8×). OE-groups exhibited prostatic hypertrophy, since prostate weight increased ∼40% in G, GL, LA, and GA and 31% in WA. As indicated by immunohistochemistry, all HFD-groups except G exhibited an increase in epithelial cell proliferation (PCNA-positive) and a decrease in frequency of AR- and ERβ-positive epithelial cells; there was also an increment of ERα-positive stromal cells in comparison with control. Cells containing PPARγ increased in both epithelium and stroma of all OE groups and those expressing LXRα decreased, particularly in groups OE-exposed during gestation (G, GL and GA).

CONCLUSIONS

OE leads to prostate hypertrophy regardless of the period of development and, except when restricted to gestation, leads to a hyperproliferative status which was correlated to downregulation of AR and LXRα and upregulation of ERα and PPARγ signaling.

The modulating effect of Persea americana fruit extract on the level of expression of fatty acid synthase complex, lipoprotein lipase, fibroblast growth factor-21 and leptin--A biochemical study in rats subjected to experimental hyperlipidemia and obesity

BACKGROUND

Obesity is a multifactorial disorder which is closely associated with hyperlipidemia. Avocados are edible fruits traditionally consumed for various health benefits including body weight reduction.

HYPOTHESIS/PURPOSE

To determine the hypolipidemic and anti-obesity effect of hydro-alcoholic fruit extract of avocado (HFEA) in rats fed with high fat diet (HFD).

STUDY DESIGN

Male Sprague Dawley rats were divided into four groups. Groups 1 and 2 rats were fed with normal diet. Groups 3 and 4 rats were fed with HFD for 14 weeks. In addition, Groups 2 and 4 rats were co-administered with 100 mg/kg body weight of HFEA from 3rd week onwards.

METHODS

The HFEA was subjected to HPLC to quantify the major phytonutrients. Body mass index (BMI), adiposity index (ADI), total fat pad mass (TFP), blood lipid levels were determined in all the groups of rats. The mRNA expression of fatty acid synthase (FASN), lipoprotein lipase (LPL), fibroblast growth factor 21 (FGF21) and leptin was also assessed.

RESULTS

HFEA was found to contain flavonoids: rutin-141.79, quercetin-5.25, luteolin-165, phenolic compounds: gallic acid-198.57, ellagic acid-238.22, vanillic acid-4.79 and phytosterols: betasitosterol-70, stigmasterol-12.5 (mg/100 g). HFEA reduced BMI, ADI, TFP, blood cholesterol, triglycerides, and LDL in rats fed with HFD. Serum leptin was found reduced in HFEA co-administered rats. The mRNA expression of FASN, LPL, and leptin in subcutaneous and visceral adipose tissue was found to be significantly reduced in HFEA co-administered rats. The gene expression of fibroblast growth factor-21 (FGF21) was found to be significantly increased in HFEA treated rats when compared to HFD control rats.

CONCLUSION

The hypolipidemic effect of HFEA may be partly due to its modulating effect on endogenous fat synthesis and adiponectin formation through the transcription factor FGF21. The results also show that avocado fruit extract has profound influence on leptin activity, which controls satiety and hunger to regulate the food intake.

Analysis of electrocorticographic patterns in rats fed standard or hyperlipidic diets in a normal state or during status epilepticus

OBJECTIVE

The consumption of hyperlipidic diets has grown markedly in recent decades, and several studies have linked this consumption with the development of neurodegenerative diseases. Conversely, hyperlipidic diets have been used as an alternative therapy for refractory epilepsy. The purpose of this study was to evaluate the effects of a hyperlipidic diet on brain electrical activity before and during status epilepticus (SE) using computational and mathematical methods.

METHODS

Electrocorticogram (ECoG) was recorded in Wistar rats fed with standard and hyperlipidic diets. Each recording was obtained during 30-minute period (baseline), after this time, the SE was induced by pilocarpine, and recording was continued for another 30 minutes. The ECoG signals were analyzed by the following methods: power spectrum, Lempel-Ziv complexity (LZC), and fractal dimension of the phase space.

RESULTS

Hyperlipidic diet in normal animals caused a decrease in the theta, alpha, and beta rhythm, and reduced the LZC of the brain electrical activity. However, when the animals were induced to SE, these differences between nutritional groups were not observed. SE caused in both dietary groups increase in theta, alpha, and beta rhythm values, and increase in the complexity of brain electrical activity.

DISCUSSION

Hyperlipidic diet consumption attenuated the brain's electrical activity, suggesting that healthy individuals who habitually eat a hyperlipidic diet may develop dysfunctions such as cognitive decline and memory impairment. Furthermore, the antagonistic effect between hyperlipidic diet and SE suggests that this diet could protect against seizures.

Effect of Persea americana (avocado) fruit extract on the level of expression of adiponectin and PPAR-γ in rats subjected to experimental hyperlipidemia and obesity

BACKGROUND

Persea americana, commonly known as avocado, is traditionally consumed fruit which possesses body fat lowering capacity. Adiponectin plays an important role in regulating obesity. In this study, the effect of hydro-alcoholic fruit extract of P. americana (HAEPA) on the level of blood lipids, glutathione, lipid peroxidation products, adiponectin and peroxisome proliferator activated receptor (PPAR)-γ expressions was investigated in rats fed a high-fat diet (HFD).

METHODS

Male Sprague Dawley rats were divided into four groups: groups 1 and 2 were fed normal rat chow (5% fat) and groups 3 and 4 were fed HFD (23% fat) for a period of 14 weeks. In addition, groups 2 and 4 rats were administered orally with 100 mg/kg body weight of HAEPA from third week. After 14 weeks, rats were sacrificed, and serum/plasma levels of total cholesterol, phospholipids, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and adiponectin were determined. The mRNA expression of adiponectin, PPAR-γ and protein expression of PPAR-γ were also evaluated.

RESULTS

The body mass index (BMI), total fat pad mass and adiposity index were significantly decreased in HAEPA co-administered rats than in HFD-fed rats. The levels of LDL and lipid peroxides were significantly higher in HFD group than in HFD+HAEPA group. Levels of reduced glutathione, adiponectin, mRNA expression of adiponectin, PPAR-γ and protein expression of PPAR-γ were found to be increased in HFD+HAEPA group than in HFD group. The hypolipidemic effect of HAEPA is also evidenced by the histological observations in liver, heart and adipose tissue.

CONCLUSIONS

The results indicate that HAEPA exhibits hypolipidemic activity probably by increasing the mRNA expression of adiponectin and PPAR-γ, which reduce the risk of hyperlipidemia and obesity.

Obesity induction with high fat sucrose in rats

BACKGROUND

Although is complex to identify the factors responsible for the important growth in obesity all over the world, the main causes are increased consumption of energy, highly saturated fats and sugars, and reduced physical activity.

AIM

To compare rats with normal and supplemented diet with sucrose in relationship to body mass, weight of gonadal and retroperitoneal fat and Lee index.

METHODS

Forty rats were divided into two groups: 20 in the control group that received normal chow diet and water for three months, and 20 animals in the experimental group who received the same diet but supplemented with sucrose 300 g/l of water. The animals were weighed once a week during 91 days. At scheduled death, they had measured the naso-anal length, body weight and Lee index. After laparotomy, retroperitoneal and gonadal fat were isolated, dried and the percentage of weight in relation to body weight at the date of death was evaluated.

RESULTS

There was a statistic significant difference between the 14th and 78th day favoring the experiment group indicating that sucrose interferes with weight gain in rats. The average weight was higher in the experimental group in all periods in comparison to initial weight. There was also significant difference in the weight of the gonadal and retroperitoneal fat. There was no significant difference comparing the Lee index.

CONCLUSION

The body mass index was higher in animals treated with diet supplemented with sucrose and had higher gonadal and retroperitoneal fat, but no difference in the Lee index.

Obesogenic environment by excess of dietary fats in different phases of development reduces spermatic efficiency of wistar rats at adulthood: correlations with metabolic status

This study compares the impact of obesogenic environment (OE) in six different periods of development on sperm parameters and the testicular structure of adult rats and their correlations with sex steroid and metabolic scenario. Wistar rats were exposed to OE during gestation (O1), during gestation/lactation (O2), from weaning to adulthood (O3), from lactation to adulthood (O4), from gestation to sexual maturity (O5), and after sexual maturation (O6). OE was induced by a 20% fat diet, and control groups were fed a balanced diet (4% fat). Serum leptin levels and adiposity index indicate that all groups were obese, except for O1. Three progressive levels of impaired metabolic status were observed: O1 presented insulin resistance, O2 were insulin resistant and obese, and groups O3, O4, and O5 were insulin resistant, obese, and diabetic. These three levels of metabolic damage were proportional to the increase of leptin and decreased circulating testosterone. The impairment in the daily sperm production (DSP) paralleled these three levels of metabolic and hormonal damage being marginal in O1, increasing in O2, and being higher in groups O3, O4, O5, and O6. None of the OE periods affected the sperm transit time in the epididymis, and the lower sperm reserves were caused mainly by impaired DSP. In conclusion, OE during sexual maturation markedly reduces the DSP at adulthood in the rat. A severe reduction in the DSP also occurs in OE exposure during gestation/lactation but not in gestation, indicating that breast-feeding is a critical period for spermatogenic impairment under obesogenic conditions.

Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation

BACKGROUND

The activation of the beta-adrenergic system promotes G protein stimulation that, via cyclic adenosine monophosphate (cAMP), alters the structure of protein kinase A (PKA) and leads to phospholamban (PLB) phosphorylation. This protein participates in the system that controls intracellular calcium in muscle cells, and it is the primary regulator of sarcoplasmic reticulum calcium pump activity. In obesity, the beta-adrenergic system is activated by the influence of increased leptin, therefore, resulting in higher myocardial phospholamban phosphorylation via cAMP-PKA.

OBJECTIVE

To investigate the involvement of proteins which regulate the degree of PLB phosphorylation due to beta-adrenergic activation in obesity. In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.

METHODS

Male Wistar rats were randomly distributed into two groups: control (n = 14), fed with normocaloric diet; and obese (n = 13), fed with a cycle of four unsaturated high-fat diets. Obesity was determined by the adiposity index, and protein expressions of phosphatase 1 (PP-1), PKA, PLB, phosphorylated phospholamban at serine16 (PPLB-Ser16) were assessed by Western blot.

RESULTS

Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.

CONCLUSION

Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.

High-calorie diet as a factor of prediabetes development in rats

We studied the key parameters of the development of prediabetic state in rats maintained on a high-calorie diet. It was found that long-term feeding a high-calorie diet increased blood concentration of glucose, glycosylated hemoglobin, and insulin and reduced the rate of glucose uptake in comparison with rats receiving standard ration.

Maternal obesity disturbs the postnatal development of gonocytes in the rat without impairment of testis structure at prepubertal age

In this study, we evaluated whether maternal obesity (MO) affects testis development and gonocyte differentiation in the rat from 0.5 to 14.5 postnatal days. Male Wistar rats were used at 0.5, 4.5, 7.5, and 14.5 days post partum (dpp). These rats were born from obese mothers, previously fed with a high-fat diet (20% saturated fat), for 15 weeks, or normal mothers that had received a balanced murine diet (4% lipids). MO did not affect testis weight or histology at birth but changed the migratory behavior of gonocytes. The density of relocated cells was higher in MO pups at 0.5 dpp, decreased at 4.5 dpp, and differed from those of control pups, where density increased exponentially from 0.5 to 7.5 dpp. The numerical density of gonocytes within seminiferous cords did not vary in MO, in relation to control neonates, for any age considered, but the testis weight was 50% lower at 4.5 dpp. A wide variation in plasmatic testosterone and estrogen levels was observed among the groups during the first week of age and MO pups exhibited higher steroid concentrations at 4.5 dpp, in comparison with controls. At this age, higher estrogen levels of MO pups impaired the gonocyte proliferation. At 7.5 dpp, the testicular size and other parameters of gonocyte development are retrieved. In conclusion, MO and saturated lipid diets disturb gonocyte development and sexual steroid levels during the first days of life, with recovery at prepubertal age.

Gastrointestinal morphological alterations in obese rats kept under hypercaloric diets

Hypercaloric diets have been successfully used as experimental models of obesity. This work compared morphological characteristics of inferior gastrointestinal organs. The experiment lasted 10 weeks, during which the rats’ food consumption, body weight, distance between the mouth and neck, distance between mouth and neck, distance between neck and tail, and abdominal circumference were evaluated weekly. After the sacrifice of the rats, 20 variables referring to inferior gastrointestinal morphology were assessed. The results comprised descriptive statistics of the data, analysis of main components, linear correlation, and t-tests. Significant differences were found between the two groups for the variables of abdominal circumference, retroperitoneal fat, ratio between retroperitoneal fat/animal weight, stomach weight, ratio between animal weight/intestine weight and mesentery/animal weight, length of small intestine, length of large intestine, and lateral line of the cecum. The data allow us to state that a hypercaloric diet can be responsible an increase in fat in the abdominal cavity as well as gastrointestinal morphological alterations, principally in stomach development.

Lycopene supplementation modulates plasma concentrations and epididymal adipose tissue mRNA of leptin, resistin and IL-6 in diet-induced obese rats

Obesity is characterised by chronic low-grade inflammation, and lycopene has been reported to display anti-inflammatory effects. However, it is not clear whether lycopene supplementation modulates adipokine levels in vivo in obesity. To determine whether lycopene supplementation can regulate adipokine expression in obesity, male Wistar rats were randomly assigned to receive a control diet (C, n 6) ora hyperenergetic diet (DIO, n 12) for 6 weeks. After this period, the DIO animals were randomised into two groups: DIO (n 6) and DIO supplemented with lycopene (DIO + L, n 6). The animals received maize oil (C and DIO) or lycopene (DIO + L, 10 mg/kg body weight(BW) per d) by oral administration for a 6-week period. The animals were then killed by decapitation, and blood samples and epididymal adipose tissue were collected for hormonal determination and gene expression evaluation (IL-6, monocyte chemoattractant protein-1(MCP-1), TNF-α, leptin and resistin). There was no detectable lycopene in the plasma of the C and DIO groups. However, the mean lycopene plasma concentration was 24 nmol in the DIO + L group. Although lycopene supplementation did not affect BW or adiposity, it significantly decreased leptin, resistin and IL-6 gene expression in epididymal adipose tissue and plasma concentrations. Also, it significantly reduced the gene expression of MCP-1 in epididymal adipose tissue. Lycopene affects adipokines by reducing leptin, resistin and plasma IL-6 levels. These data suggest that lycopene may be an effective strategy in reducing inflammation in obesity.

Efeito da redução de ninhada sobre as respostas autonômicas e metabólicas de ratos Wistar

OBJETIVO: Este estudo investigou o perfil lipídico e a atividade elétrica dos nervos parassimpático (vago superior) e simpático (localizado na região esplâncnica) de ratos obesos oriundos de ninhada reduzida. MÉTODOS: Foram pesquisados dois grupos distintos, com 12 animas cada um: ninhada padrão, padronizado em nove filhotes por ninhada, e ninhada reduzida, três filhotes por ninhada. O consumo de ração e peso corporal foi acompanhado do desmame até o final do protocolo experimental. Aos 90 dias de idade, os animais foram anestesiados com (Thiopental®) e submetidos ao registro da atividade elétrica dos nervos simpático (vago) e parassimpático (da região esplâncnica); em seguida, foram sacrificados e retiradas e pesadas as gorduras retroperitoneal e periepididimal. Amostras de sangue foram coletadas para dosagens de glicemia, insulinemia, colesterol total, triglicerídeos e lipoproteína de alta densidade colesterol. RESULTADOS: Os ratos de ninhada reduzida apresentaram aumento da ingestão alimentar, peso corporal e tecido adiposo branco, quadros de hiperglicemia, hiperinsulinemia e hipercolesterolemia, aumento dos triglicérides e redução do lipoproteína de alta densidade colesterol. CONCLUSÃO: Quanto à atividade do nervo vago, os ratos ninhada reduzida apresentaram um aumento significativo em relação aos ratos ninhada padrão, e mesmo não havendo diferença na atividade simpática, o modelo ninhada reduzida mostrou-se eficaz para indução da obesidade, dislipidemia, hipercolesterolemia, hiperinsulinemia, hiperglicemia e desequilíbrio autonômico em roedores.