High fructose-containing drinking water-induced steatohepatitis in rats is prevented by the nicotinamide-mediated modulation of redox homeostasis and NADPH-producing enzymes

Integrated network pharmacology, transcriptomics and metabolomics to explore the material basis and mechanism of Danggui-Baishao herb pair for treating hepatic fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

The Danggui-Baishao herb pair (DB) is commonly used as Chinese herbal formulas for treating hepatic fibrosis (HF). However, there are few research on the combined application of the two drugs in treating HF, and the precise mechanisms and fundamental components of DB in addressing HF are still unclear.

AIM OF THE STUDY

The intention of this research is to identify the molecular foundation and functional targets of DB to elucidate the mechanisms for treating HF.

METHODS

The ingredients absorbed from DB in rat plasma were analyzed using UPLC-QE-MS. Therapeutic efficacy of DB in a rat model of CCl4-induced HF assessed using biochemical indices, pathological tissue observations, immunohistochemical and western blotting. An integrated strategy of transcriptomics, metabolomics, and network pharmacology was then utilized to explain the possible material basis and mechanisms of DB for treating HF. Western blotting was carried out to verify the critical mechanism.

RESULTS

DB reduced the level of liver function and inflammation related indicators in CCl4-induced HF (P < 0.05 or P < 0.01), as well as ameliorated pathological histological changes, and reduced the expressions of collagen type I (Col-I) and α-smooth muscle actin (α-SMA). Nineteen ingredients absorbed from DB were identified. Comprehensive investigations of transcriptomics, metabolomics, and network pharmacology revealed that DB modulated the PI3K/Akt/NF-κB signaling pathway to ameliorate fibrosis induced by CCl4 in HF rats. According to the molecular docking results, core tagets were highly favored by kaempferol, benzoylpaeoniflorin, albiflorin, paeoniflorin, and levistilide A.

CONCLUSIONS

The possible mechanisms for DB treatment of HF include decreasing the activity of hepatic stellate cells (HSCs), decreasing collagen synthesis and deposition, attenuating the hepatic inflammatory response, inhibiting hepatocyte apoptosis, and increasing the level of niacinamide (NAM), thus exerting its anti-HF effect.

Metabolomic and biochemical changes in the plasma and liver of toxic milk mice model of Wilson disease

Wilson disease (WD) is an inherited disorder characterized by abnormal copper metabolism with complex pathological features. Currently, this mechanism of copper overload-induced hepatic injury remains unclear. In this study, male toxic milk (TX) mice were selected as experimental subjects. Copper levels and biochemical indices were measured by atomic absorption spectroscopy (AAS) and kits. Liver tissue ultrastructure was observed by hematoxylin-eosin (H&E), sirius red staining and transmission electron microscopy. Plasma and liver metabolic profiles of TX mice were characterized by untargeted metabolomics. In addition, the expression of enzymes related to arachidonic acid metabolism in liver tissue was detected by Western blotting. The results showed the excessive copper content, concomitant oxidative stress, and hepatic tissue structural damage in TX mice. Seventy-eight metabolites were significantly different in WD, mainly involved in the metabolism of arachidonic acid, glycerophospholipids, sphingolipids, niacin and nicotinamide, and phenylalanine. Furthermore, the arachidonic acid metabolic pathway is an important pathway involved in WD metabolism. The level of arachidonic acid in the liver of TX mice was significantly lower (p < 0.01) compared to the control group. The expression of cytoplasmic phospholipase A2 (cPLA2) and arachidonic acid 12-lipoxygenase (ALOX12), related to the arachidonic acid metabolic pathway, was significantly different in the liver of TX mice (p < 0.01). Modulation of the arachidonic acid metabolic pathway could be a potential therapeutic strategy to alleviate WD symptoms.

Fennel seeds extract prevents fructose-induced cardiac dysfunction in a rat model of metabolic syndrome via targeting abdominal obesity, hyperuricemia and NF-κβ inflammatory pathway

BACKGROUND

Metabolic syndrome (MetS) is commonly associated with increased risk of cardiac disease that affects a large number of world populations.

OBJECTIVE

This research attempted to investigate the efficacy of fennel seeds extract (FSE) in preventing development of cardiac dysfunction in rats on fructose enriched diet for 3 months, as a model of MetS.

MATERIALS & METHODS

Thirty adult Wistar male rats (160-170 g) were assigned into 5 groups including control, vehicle, FSE (200 mg/kg BW) and fructose (60%) fed rats with and without FSE. Following the last treatment, blood pressure, ECG and heart rate were measured. Next, blood and cardiac tissues were taken for biochemical and histological investigations.

RESULTS

Feeding fructose exhibited characteristic features of MetS involving, hypertension, abnormal ECG, elevated heart rate, serum glucose, insulin, lipids and insulin resistance, accompanied by abdominal obesity, cardiac hypertrophy and hyperuricemia. Fructose fed rats also showed significant reduction in cardiac antioxidants (GSH, SOD, CAT) with elevation in oxidative stress indices (NADPH oxidase, O2.-, H2O2, MDA, PCO), NF-κβ, pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), adhesion molecules (ICAM-1, VCAM-1) and serum cardiac biomarkers (AST, LDH, CK-MB, cTn-I). Histopathological changes evidenced by destruction of cardiac myofibrils, cytoplasmic vacuolization, and aggregation of inflammatory cells were also detected. Consumption of FSE showed high ability to alleviate fructose-induced hypertension, ECG abnormalities, cardiac hypertrophy, metabolic alterations, oxidative stress, inflammation and histological injury.

CONCLUSION

Findings could suggest FSE as a complementary supplement for preventing MetS and associated cardiac outcomes. However, well controlled clinical studies are still needed.

Proteomic and metabolomic analysis of GH deficiency-induced NAFLD in hypopituitarism: insights into oxidative stress

Objective

Individuals with hypopituitarism (HPs) have an increased risk of developing non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) due to growth hormone deficiency (GHD). We aimed to investigate the possible mechanisms underlying the relationship between GHD and NAFLD using proteomic and metabolomic insights.

Methods

Serum metabolic alternations were assessed in male HPs using untargeted metabolomics. A rat model of HP was established through hypophysectomy, followed by recombinant human growth hormone (rhGH) intervention. The mechanisms underlying GHD-mediated NAFLD were elucidated through the application of label-free proteomics and phosphorylation proteomics.

Results

Metabolomic analysis revealed that biomarkers of mitochondrial dysfunction and oxidative stress, such as alanine, lactate, and creatine, were significantly elevated in HPs compared to age-matched controls. In rats, hypophysectomy led to marked hepatic steatosis, lipid peroxidation, and reduced glutathione (GSH), which were subsequently modulated by rhGH replacement. Proteomic analysis identified cytochrome P450s, mitochondrial translation elongation, and PPARA activating genes as the major distinguishing pathways in hypophysectomized rats. The processes of fatty acid transport, synthesis, oxidation, and NADP metabolism were tightly described. An enhanced regulation of peroxisome β-oxidation and ω-oxidation, together with a decreased NADPH regeneration, may exacerbate oxidative stress. Phosphoproteome data showed downregulation of JAK2-STAT5B and upregulation of mTOR signaling pathway.

Conclusions

This study identified proteo-metabolomic signatures associated with the development of NAFLD in pituitary GHD. Evidence was found of oxidative stress imbalance resulting from abnormal fatty acid oxidation and NADPH regeneration, highlighting the role of GH deficiency in the development of NAFLD.

Examining the Pathogenesis of MAFLD and the Medicinal Properties of Natural Products from a Metabolic Perspective

Metabolic-associated fatty liver disease (MAFLD), characterized primarily by hepatic steatosis, has become the most prevalent liver disease worldwide, affecting approximately two-fifths of the global population. The pathogenesis of MAFLD is extremely complex, and to date, there are no approved therapeutic drugs for clinical use. Considerable evidence indicates that various metabolic disorders play a pivotal role in the progression of MAFLD, including lipids, carbohydrates, amino acids, and micronutrients. In recent years, the medicinal properties of natural products have attracted widespread attention, and numerous studies have reported their efficacy in ameliorating metabolic disorders and subsequently alleviating MAFLD. This review aims to summarize the metabolic-associated pathological mechanisms of MAFLD, as well as the natural products that regulate metabolic pathways to alleviate MAFLD.

Nicotinamide, an acetylcholinesterase uncompetitive inhibitor, protects the blood‒brain barrier and improves cognitive function in rats fed a hypercaloric diet

Oxidative stress and inflammation induced by abundant consumption of high-energy foods and caloric overload are implicated in the dysfunction of the blood‒brain barrier (BBB), cognitive impairment, and overactivation of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These enzymes hydrolyse acetylcholine, affecting anti-inflammatory cholinergic signalling. Our aim was to evaluate whether nicotinamide (NAM) attenuates the impairment of the BBB and cognitive function, improving cholinergic signalling. Forty male rats were distributed into five groups: one group was fed a standard diet, and the remaining groups were fed a high-fat diet and a beverage with 40% sucrose (HFS; high-fat sucrose). In three of the HFS groups, the carbohydrate was replaced by drinking water containing different concentrations of NAM for 5 h every morning for 12 weeks. The biochemical profile, levels of stress and inflammation markers, cholinesterase activities, BBB permeability, and cognitive capacity were evaluated. The results showed that the HFS diet disturbed the metabolism of carbohydrates and lipids, causing insulin resistance. Simultaneously, AChE and BChE activities, levels of proinflammatory cytokines, oxidation of proteins and lipoperoxidation increased along with decreased antioxidant capacity in serum. In the hippocampus, increased activity of cholinesterases, protein carbonylation and lipoperoxidation were associated with decreased antioxidant capacity. Systemic and hippocampal changes were reflected in increased BBB permeability and cognitive impairment. In contrast, NAM attenuated the above changes by reducing oxidative stress and inflammation through decreasing cholinesterase activities, especially by uncompetitive inhibition. NAM may be a potential systemic and neuroprotective agent to mitigate cognitive damage due to hypercaloric diets.

Physiological, metabolomic, and transcriptomic reveal metabolic pathway alterations in Gymnocypris przewalskii due to cold exposure

Teleost fish have evolved various adaptations that allow them to tolerate cold water conditions. However, the underlying mechanism of this adaptation is poorly understood in Tibetan Plateau fish. RNA-seq combined with liquid chromatography‒mass spectrometry (LC‒MS/MS) metabolomics was used to investigate the physiological responses of a Tibetan Plateau-specific teleost, Gymnocypris przewalskii, under cold conditions. The 8-month G. przewalskii juvenile fish were exposed to cold (4 ℃, cold acclimation, CA) and warm (17 ℃, normal temperature, NT) temperature water for 15 days. Then, the transcript profiles of eight tissues, including the brain, gill, heart, intestine, hepatopancreas, kidney, muscle, and skin, were evaluated by transcriptome sequencing. The metabolites of the intestine, hepatopancreas, and muscle were identified by LC‒MS/MS. A total of 5,745 differentially expressed genes (DEGs) were obtained in the CA group. The key DEGs were annotated using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The DEGs from the eight tissues were significantly enriched in spliceosome pathways, indicating that activated alternative splicing is a critical biological process that occurs in the tissues to help fish cope with cold stress. Additionally, 82, 97, and 66 differentially expressed metabolites were identified in the intestine, hepatopancreas, and muscle, respectively. Glutathione metabolism was the only overlapping significant pathway between the transcriptome and metabolome analyses in these three tissues, indicating that an activated antioxidative process was triggered during cold stress. In combination with the multitissue transcriptome and metabolome, we established a physiology-gene‒metabolite interaction network related to energy metabolism during cold stress and found that gluconeogenesis and long-chain fatty acid metabolism played critical roles in glucose homeostasis and energy supply.

Pancreatic β-Cell Apoptosis in Normoglycemic Rats is Due to Mitochondrial Translocation of p53-Induced by the Consumption of Sugar-Sweetened Beverages

Overstimulation of pancreatic β-cells can lead to dysfunction and death, prior to the clinical manifestations of type 2 diabetes (T2D). The excessive consumption of carbohydrates induces metabolic alterations that can affect the functions of the β-cells and cause their death. We analyzed the role of p53 in pancreatic β cell death in carbohydrate-supplemented Sprague Dawley rats. For four months, the animals received drinking water containing either 40% sucrose or 40% fructose. The glucose tolerance test was performed at week 15. Apoptosis was assessed with the TUNEL assay (TdT-mediated dUTP-nick end-labeling). Bax, p53, and insulin were assessed by Western blotting, immunofluorescence, and real-time quantitative PCR. Insulin, triacylglycerol, and serum glucose and fatty acids in pancreatic tissue were measured. Carbohydrate consumption promotes apoptosis and mobilization of p53 from the cytosol to rat pancreatic β-cell mitochondria before blood glucose rises. An increase in p53, miR-34a, and Bax mRNA was also detected (P < 0.001) in the sucrose group. As well as hypertriglyceridemia, hyperinsulinemia, glucose intolerance, insulin resistance, visceral fat accumulation, and increased pancreatic fatty acids in the sucrose group. Carbohydrate consumption increases p53 and its mobilization into β-cell mitochondria and coincides with the increased rate of apoptosis, which occurs before serum glucose levels rise.

Nicotinamide supplementation alters plasma lipidomic profiles of peripartal dairy cows

Fatty liver syndrome, a common health problem in dairy cows, occurs during the transition from pregnancy to lactation. If the energy supplied to the cow's body cannot meet its needs, a negative energy balance ensues, and the direct response is fat mobilization. Nicotinamide (NAM) has been reported to reduce the nonesterified fatty acid concentration of postpartum plasma. To study the biochemical adaptations underlying this physiologic dysregulation, 12 dairy cows were sequentially assigned to a NAM (45 g/day) treatment or control group. Blood samples were collected on day (D) 1 and D21 relative to parturition. Changes to the plasma lipid metabolism of dairy cows in the two groups were compared using lipidomics. There were significant increases in plasma sphingomyelins d18:1/18:0, d18:1/23:0, d18:1/24:1, d18:1/24:0, and d18:0/24:0 in the NAM group on D1 relative to parturition. In addition, fatty acids 18:2, 18:1, 18:0, 16:1, and 16:0 were obviously decreased on D21 relative to calving. This research has provided insights into how NAM supplementation improves lipid metabolism in perinatal dairy cows.

Effects of resveratrol on lipid metabolism in liver of red tilapia Oreochromis niloticus

Resveratrol (RES), as a polyphenol natural plant extract, mainly accumulates in the root of Polygonum cuspidatum, which can alleviate liver injury in mammals. Our study aims to explore the effects and potential mechanism of RES on lipid metabolism of red tilapia, and the effects of RES on liver structure, fat synthesis and metabolism of red tilapia were determined. The present study designed four groups named as 8 % fat (8%CK), 10 % fat (10 % HF), 10 % HF + RES and 10 % HF + RES + EX527 (selisistat). The liver tissues of red tilapia were collected at 3 (3 W), 6 (6 W) and 9 (9 W) weeks for parameter determination. Compared to the normal diet group, the hepatocyte of tilapia showed nuclear shift and vacuoles of different sizes when fed a high-fat diet. Meanwhile, the high-fat diet increased the contents of LDL, TC and TG significantly at 6 W, and significantly decreased the content of NAD⁺ at 9 W. Compared to the high-fat group, the nuclei of tilapia fed with RES were increased and visible, the degree of steatosis and the number of vacuoles were both reduced. At 3/6/9 W, RES significantly decreased the contents of LDL, TG and TMAO, and significantly increased the content of NAD⁺. A total of 1416 genes were up-regulated and 1928 genes were down-regulated in the group with added RES when compared to the 10 % HF group. The pathways related to lipid metabolism including PPAR signaling pathway have been enriched. Interestingly, the expressions of sirt1, pparα, fabp7 and cpt1b genes were up-regulated in RES diet group, while the expressions of pparγ, me1, scd and lpl genes were down-regulated. After the addition of an inhibitor (EX527), the above indexes showed an opposite trend when compared to the group with added RES. The overall results showed that the high-fat diet could cause fatty liver lesions in the liver of red tilapia, and RES could activate the sirt1 gene, regulate the PPARα/γ pathway and related genes, and thus regulate liver fat synthesis and metabolism leading to the alleviation of damage to liver tissue.

Effects of nicotinamide on follicular development and the quality of oocytes

BACKGROUND

Nicotinamide (NAM) is an important antioxidant, which is closely related to female fertility, but its role has not been clearly elucidated. The purpose of the present study was to investigate the effects of NAM on follicular development at different stages and the quality of oocytes.

METHODS

The concentration of NAM in follicular fluid (FF) of 236 women undergoing in vitro fertilization (IVF) was ascertained by enzyme-linked immunosorbent assay (ELISA), and the correlation between NAM and clinical indexes was analyzed. During the in vitro maturation (IVM) of mice cumulus-oocyte complexes (COCs), different concentrations of NAM were added to check the maturation rate and fertilization rate. The reactive oxygen species (ROS) levels in the oocytes treated with different hydrogen peroxide (H₂O₂) and NAM were assessed. Immunofluorescence staining was performed to measure the proportion of abnormal spindles.

RESULTS

The level of NAM in large follicles was significantly higher than that in small follicles. In mature FF, the NAM concentration was positively correlated with the rates of oocyte maturation and fertilization. Five mM NAM treatment during IVM increased maturation rate and fertilization rate in the oxidative stress model, and significantly reduced the increase of ROS levels induced by H₂O₂ in mice oocytes.

CONCLUSIONS

Higher levels of NAM in FF are associated with larger follicle development. The supplement of 5 mM NAM during IVM may improve mice oocyte quality, reducing damage caused by oxidative stress.

Fructose and Non-Alcoholic Steatohepatitis

Background: The excessive consumption of free sugars is mainly responsible for the high prevalence of obesity and metabolic syndrome in industrialized countries. More and more studies indicate that fructose is involved in the pathophysiology and also in the degree of disease of non-alcoholic fatty liver disease (NAFLD). In epidemiologic studies, energy-adjusted higher fructose consumption correlates with NAFLD in overweight adults. In addition to glucose, fructose, as an equivalent component of conventional household sugar, appears to have negative metabolic effects in particular due to its exclusive hepatic metabolism. Liver-related mortality is strictly associated with the degree of fibrosis, whereas the most common cause of death in patients suffering from NAFLD and non-alcoholic steatohepatitis (NASH) are still cardiovascular diseases. In this review article, we have summarized the current state of knowledge regarding a relationship between fructose consumption, liver fibrosis and life expectancy in NASH. Method: Selective literature search in PubMed using the keywords 'non-alcoholic fatty liver', 'fructose', and 'fibrosis' was conducted. Results: The rate of overweight and obesity is significantly higher in both, adult and pediatric NASH patients. The consumption of free sugars is currently three times the maximum recommended amount of 10% of the energy intake. The current literature shows weight gain, negative effects on fat and carbohydrate metabolism and NASH with hypercaloric intake of fructose. Conclusions: Excessive fructose consumption is associated with negative health consequences. Whether this is due to an excess of energy or the particular metabolism of fructose remains open with the current study situation. The urgently needed reduction in sugar consumption could be achieved through a combination of binding nutritional policy measures including taxation of sugary soft drinks. Previous studies suggest that diet-related fructose intake exceeding the amount contained in vegetables and fruits lead to an increase of hepatic lipogenesis. Thus, further studies to clarify the protective contribution of low-fructose intake to positively influence NAFLD in industrial population are urgently required.

The role of microRNA-33 as a key regulator in hepatic lipogenesis signaling and a potential serological biomarker for NAFLD with excessive dietary fructose consumption in C57BL/6N mice

Limited studies reported mechanisms by which microRNAs (miRNA) are interlinked in the etiology of fructose-induced non-alcoholic fatty liver disease (NAFLD). Here, we aimed to investigate the significance of miRNAs in fructose-induced NAFLD pathogenesis through unbiased approaches. In experiment I, C57BL/6N mice were fed either water or 34% fructose for six weeks ad libitum. In experiment II, time course effects of fructose intervention were monitored using the same conditions; mice were killed at the baseline, fourth, and sixth weeks. Bioinformatic analyses for hepatic proteomics revealed that SREBP1 is the most significant upstream regulator influenced by fructose; miR-33-5p (miR-33) was identified as the key miRNA responsible for SREBP1 regulation upon fructose intake, which was validated by in vitro transfection assay. In experiment II, we confirmed that the longer mice consumed fructose, the more severe liver injury markers (e.g., serum AST) appeared. Moreover, hepatic Srebp1 mRNA expression was increased depending upon the duration of fructose consumption. Hepatic miR-33 was time-dependently decreased by fructose while serum miR-33 expression was increased; these observations indicated that miR-33 from the liver might be released upon cell damage. Finally we observed that fructose-induced ferroptosis might be a cause of liver toxicity, resulting from oxidative damage. Collectively, our findings suggest that fructose-induced oxidative damage induces ferroptosis, and miR-33 could be used as a serological biomarker of fructose-induced NAFLD.

Reduction of fatty liver in rats by nicotinamide via the regeneration of the methionine cycle and the inhibition of aldehyde oxidase

Nonalcoholic fatty liver disease, which has been rapidly increasing in the world in recent years, is roughly classified into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis. This study was based on our previous reports that stated that the combination treatment of N1-methylnicotinamide (MNA) and hydralazine (HYD) improves fatty liver in NAFL model rats. This finding was attributed to the MNA metabolism inhibition by HYD, which is a strong inhibitor of aldehyde oxidase (AO); this results in an increase in hepatic MNA and improved fatty liver. We hypothesized that orally administered nicotinamide (NAM), which is the precursor of MNA and is a form of niacin, would be efficiently metabolized by nicotinamide N-methyltransferase in the presence of exogenous S-adenosylmethionine (SAM) in NAFL rats. To address this issue, NAFL model rats were orally administered with NAM, SAM, and/or HYD. As a result, liver triglyceride (TG) and lipid droplet levels were barely altered by the administration of NAM, SAM, NAM+SAM, or NAM+HYD. By contrast, the triple combination of NAM+SAM+HYD significantly reduced hepatic TG and lipid droplet levels and significantly increased hepatic MNA levels. These findings indicated that the combination of exogenous SAM with AO inhibitors, such as HYD, has beneficial effects for improving fatty liver with NAM.

Echography analysis of musculoskeletal, heart and liver alterations associated with endothelial dysfunction in obese rats

BACKGROUND

Modern imaging plays a central role in the care of obese patients, and there is an integral focus on its use and accessibility in individuals who have alterations of various in various organs. The objective in this study was to perform an echographic analysis of musculoskeletal system disorders, endothelial dysfunction and the left ventricle (LV) in obese rats.

METHODS

Sprague Dawley rats (250 ± 5 g) were obtained and divided into two groups: the control (C) group was fed with a standard diet, and the obese (Ob) group was fed hyper caloric diet with a high fructose-fat content for 4 months. Body weight, cholesterol, triglycerides, glucose, inflammatory cytokines and adhesion molecules (ICAM-1, VCAM-1) were measured. Additionally, two-dimensional echocardiography, abdominal ultrasound and musculoskeletal system studies were performed in the lower extremities.

RESULTS

The body weight in the Ob group was increased compared to that in the control group, (p < 0.001); in addition, increased glucose, cholesterol and triglyceride concentrations (p < 0.05) as well as increased levels of the adhesion molecules ICAM-1 and, VCAM-1 (p < 0.01) were found in the Ob group vs the C group. On ultrasound, 75% of the Ob group presented fatty liver and distal joint abnormalities.

CONCLUSION

Obese rats exhibit endothelial dysfunction and musculoskeletal changes, also, fatty liver and articular cysts in the posterior region of the distal lower- extremity joints.

The gonadal expression pattern of lipocalin‑2 and 24p3 receptor is modified in the gonads of the offspring of obese rats

Obesity represents a global health and economic burden, affecting millions of individuals worldwide. This pathology is associated with a chronic low-grade inflammatory state that is partially responsible for the development of other cardiometabolic complications. Clinical studies have reported an association between high circulating levels of lipocalin-2 (Lcn2) and increased body weight. Additionally, there is scientific evidence demonstrating the impact of maternal obesity on fetal programming. The latter and the fact that the authors previously found that Lcn2 and its receptor (24p3R) are expressed in the gonads of wild-type rats, led to the analysis of their mRNA profile and cellular localization in gonads collected from the offspring of obese rats at 21 days postconception (dpc), and 0, 2, 4, 6, 12, 20 and 30 days postnatal (dpn) in the present study. Semi-quantitative PCR revealed a statistically significant downregulation of Lcn2 and 24p3R mRNA at 21 dpc in the ovaries (P<0.01) and testicles (P<0.001) of the offspring of obese mothers. At 30 dpn, the relative expression of Lcn2 mRNA decreased significantly in the ovaries of the experimental group (P<0.05), while Lcn2 mRNA expression was not detectable in testicles. Regarding 24p3R, its mRNA was only significantly decreased at 21 dpc in ovaries of pups of obese mothers. At 30 dpn, the change in females was not significant. Conversely, in testicles, 24p3R mRNA levels increased slightly in the experimental group at 30 dpn. The Lcn2 protein signal was less intense in gonadal tissue sections from 30 dpn offspring of obese rats (P<0.001), whereas the 24p3R signal was downregulated in ovaries (P<0.001) and slightly upregulated in testicles. It was concluded that maternal obesity changes the expression of Lcn2 and 24p3R in the gonads of the offspring of obese rats, possibly through fetal programming. The consequences of this dysregulation for the offspring's gonadal function remains to be determined.

Nicotinamide reduces inflammation and oxidative stress via the cholinergic system in fructose-induced metabolic syndrome in rats

AIMS

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) have been associated with risk factors for metabolic syndrome (MetS). Our objective was to evaluate the effect of nicotinamide (NAM) on the activities, expression and protein content of cholinesterases in a MetS model.

MAIN METHODS

MetS was induced in male rats administrating 40% fructose to the drinking water for 16 weeks. Additionally, from 5th week onward, the carbohydrate solution was replaced by NAM, at several concentrations for 5 h each morning for the next 12 weeks. In the 15th week, the glucose tolerance test was conducted, and blood pressure was measured. After the treatment period had concluded, the biochemical profile; oxidant stress; proinflammatory markers; and the activity, quantity and expression of cholinesterases were evaluated, and molecular docking analysis was performed.

KEY FINDINGS

The MetS group showed anthropometric, hemodynamic and biochemical alterations and increased cholinesterase activity, inflammation and stress markers. In the liver, cholinesterase activity and mRNA, free fatty acid, tumor necrosis factor-alpha (TNF-α), and thiobarbituric acid-reactive substance (TBARS) levels were increased, while reduced glutathione (GSH) levels were decreased. NAM partially or totally decreased risk factors for MetS, markers of stress and inflammation, and the activity (serum and liver) and expression (liver) of cholinesterases. Molecular docking analysis showed that NAM has a greater affinity for cholinesterases than acetylcholine (ACh), suggesting NAM as an inhibitor of cholinesterases.

SIGNIFICANCE

Supplementation with 40% fructose induced MetS, which increased the activity and expression of cholinesterases, oxidative stress and the inflammation. NAM attenuated these MetS-induced alterations and changes in cholinesterases.