Research on the effects of L-carnitine and trans-chalcone on endoplasmic reticulum stress and oxidative stress in high-fructose corn syrup-fed rats

The protective role of selenium against high-fructose corn syrup-induced kidney damage: a histopathological and molecular analysis

With the growth of the food industry, fructose, the intake of which increases with food, causes obesity and metabolic syndrome. Kidney damage may develop from metabolic syndrome. Selenium (Se) participates in the structure of antioxidant enzymes and has a medicinal effect. In this work, the protective impact of Se on kidney damage produced by high-fructose corn syrup (HFCS) via endoplasmic reticulum (ER) stress was examined. The study comprised four groups, each consisting of ten experimental animals: control, HFCS (20%-HFCS), HFCS (20%-HFCS), + Se (0.3 mg/kg/day/po), and Se (0.3 mg/kg/day/po) alone. The duration of the experiment was 6 weeks. Kidney tissues were stained with hematoxylin and eosin for histological examination. Immunohistochemical analysis was conducted to assess TNF-α and caspase-3 levels. The spectrophotometric evaluation was performed to measure TOS (total oxidant status), TAS (total antioxidant status), and OSI (oxidative stress index) levels. The PERK, ATF4, CHOP, BCL-2, and caspase-9 gene expression levels were assessed by the RT-qPCR method. After Se treatment, histopathological abnormalities and TNF-α and caspase-3 levels in the HFCS+Se group decreased (p < 0.001). While TOS and OSI levels increased dramatically in the HFCS group, TAS values decreased significantly but improved after Se application (p < 0.001). The expression levels of the genes PERK, ATF4, CHOP, and caspase-9 were significantly lower in the HFCS group when compared to the HFCS+Se group (p < 0.05). Our findings suggest that Se may protect against ER stress, oxidative stress, apoptosis, and kidney damage caused by high-dose fructose consumption.

Argon non-thermal plasma treatment promotes the development of rice (Oryza sativa L.) in saline alkali environments

Soil salinization leads to a reduction in arable land area, which seriously endangers food security. Developing saline-alkali land has become a key measure to address the contradiction between population growth and limited arable land. Rice is the most important global food crop, feeding half of the world's population and making it a suitable choice for planting on saline-alkali lands. The traditional salt-alkali improvement method has several drawbacks. Currently, non-thermal plasma (NTP) technology is being increasingly applied in agriculture. However, there are few reports on the cultivation of salt/alkali-tolerant rice. Under alkaline stress, argon NTP treatment significantly increased the germination rate of Longdao 5 (LD5) rice seeds. In addition, at 15 kV and 120 s, NTP treatment significantly increased the activity of antioxidant enzymes such as catalase and SOD. NTP treatment induced changes in genes related to salt-alkali stress in rice seedlings, such as chitinase and xylanase inhibitor proteins, which increased the tolerance of the seeds to salt-alkali stress. This experiment has expanded the application scope of NTP in agriculture, providing a more cost-effective, less harmful, and faster method for developing salt-alkali-tolerant rice and laying a theoretical foundation for cultivating NTP-enhanced salt-alkali-tolerant rice.

Protective effect of vitamin D on learning and memory impairment in rats induced by high fructose corn syrup

In our study, we aimed to investigate the negative effects of the prefrontal cortex (PFC)-associated impairment of cholinergic activity on memory and learning caused by high fructose corn syrup (HFCS) and the protective role of vitamin D in adolescent rats. Twenty-four animals were divided into three groups as control, HFCS group (11 % HFCS-55 solution, ad libitum) and HFCS+ Vit D (42 μg/kg/day). Elevated Plus Maze (EPM), Forced Swim Test (FST), and Morris Water Maze (MWM, performed from day 23) tests were applied to all animals. Fluid intake consumption of the rats was measured daily, weight gain and blood glucose were measured weekly. After 31 days of treatment, the rats were sacrificed and PFC tissue was removed for biochemical, histopathological and immunohistochemical analyses. In HFCS group, fluid consumption, blood glucose, malondialdehyde (MDA) levels, degenerative neuron count and choline acetyltransferase (ChAT) expression were significantly increased; superoxide dismutase (SOD), catalase (CAT) enzyme activity and brain-derived neurotrophic factor (BDNF) expression were significantly decreased. In addition, the time spent in the enclosed arm in EPM was increased, the immobility time in FST was, and the time spent in the target quadrant in MWM was significantly decreased. Vitamin D treatment reversed all these parameters. In conclusion, HFCS caused an increase in the number of degenerative neurons in the PFC, disrupted cholinergic activity and negatively affected learning-memory functions. Vitamin D, decreased the number of degenerative neurons, increased cholinergic activity and positively affected learning and memory performance. BRIEF SYNOPSIS: In this study, prefrontal cortex damage was investigated in adolescent rats fed high fructose corn syrup. The effect of vitamin D on prefrontal cortex damage was evaluated.

Dietary l-carnitine regulates liver lipid metabolism via simultaneously activating fatty acid β-oxidation and suppressing endoplasmic reticulum stress in large yellow croaker fed with high-fat diets

Dietary l-carnitine (LC) is a nutritional factor that reduces liver lipid content. However, whether dietary LC can improve lipid metabolism via simultaneous activation of mitochondrial fatty acid (FA) β-oxidation and suppression of endoplasmic reticulum (ER) stress is still unknown. Large yellow croaker were fed with a high-fat diet (HFD) supplemented with dietary LC at 0, 1·2 or 2·4 ‰ for 10 weeks. The results indicated that a HFD supplemented with LC reduced the liver total lipid and TAG content and improved serum lipid profiles. LC supplementation administered to this fish increased the liver antioxidant capacity by decreasing serum and liver malondialdehyde levels and enhancing the liver antioxidant capacity, which then relieved the liver damage. Dietary LC increased the ATP dynamic process and mitochondrial number, decreased mitochondrial DNA damage and enhanced the protein expression of mitochondrial β-oxidation, biogenesis and mitophagy. Furthermore, dietary LC supplementation increased the expression of genes and proteins related to peroxisomal β-oxidation and biogenesis. Interestingly, feeding fish with LC-enriched diets decreased the protein levels indicative of ER stress, such as glucose-regulated protein 78, p-eukaryotic translational initiation factor 2a and activating transcription factor 6. Dietary LC supplementation downregulated mRNA expression relative to FA synthesis, reduced liver lipid and relieved liver damage through regulating β-oxidation and biogenesis of mitochondria and peroxisomes, as well as the ER stress pathway in fish fed with HFD. The present study provides the first evidence that dietary LC can improve lipid metabolism via simultaneously promoting FA β-oxidation capability and suppressing the ER stress pathway in fish.

Dietary l-carnitine supplementation recovers the increased pH and hardness in fillets caused by high-fat diet in Nile tilapia (Oreochromis niloticus)

The wide use of high-fat diet (HFD) causes negative effects on flesh quality in farmed fish. l-carnitine, a lipid-lowering additive, enhances mitochondrial fatty acid β-oxidation. However its roles in alleviating the effects of HFD on flesh quality in fish are unknown. We fed Nile tilapia with medium-fat diet (MFD, 6% dietary lipid), high-fat diet (HFD, 12% dietary lipid) and HFCD supplemented with l-carnitine (HFCD + 400 mg/kg l-carnitine) for 10 weeks. The HFD-fed fish had higher fat deposition, pH value, myofiber density and flesh hardness than those fed on MFD. However, feeding the fish with the HFCD improved lipid catabolism, which increased significantly lactic acid content and myofiber diameter in muscle, thus reduced pH and hardness values. HFCD also reduced endoplasmic reticulum stress and myofiber apoptosis caused by HFD in the fish. Our study suggests that dietary l-carnitine supplementation alleviates the negative effects of HFD on flesh quality of farmed fish.

ER stress in obesity pathogenesis and management

Given the unprecedented global pandemic of obesity, a better understanding of the etiology of adiposity will be necessary to ensure effective management of obesity and related complications. Among the various potential factors contributing to obesity, endoplasmic reticulum (ER) stress refers to a state of excessive protein unfolding or misfolding that is commonly found in metabolic diseases including diabetes mellitus, insulin resistance (IR), and non-alcoholic fatty liver disease, although its role in obesogenesis remains controversial. ER stress is thought to drive adiposity by dampening energy expenditure, making ER stress a likely therapeutic target for the management of obesity. We summarize the role of ER stress and the ER stress response in the onset and development of obesity, and discuss the underlying mechanisms involved with a view to identifying novel therapeutic strategies for obesity prevention and management.

The Effects of Probiotics and Omega-3 Fatty Acids in Liver Steatosis Induced in Rats by High-Fructose Corn Syrup

AIMS

This study was designed to reveal the effect of probiotics and omega-3 fatty acids in a fatty liver model in rats induced by high-fructose corn syrup (HFCS).

METHODS

In the study, 40 male Wistar Albino rats were used, and these rats were divided into five groups. HFCS was added to the drinking water (30% solution) of four groups (Groups 2, 3, 4, and 5) for three weeks, and the animals were fed ad libitum. At the end of three weeks, the rats in Groups 3, 4, and 5 were administered omega-3 fatty acids (400 mg/kg) and probiotics (1.5 × 10⁹ cfu/mL/day) with the gavage method for four weeks. The body weights of rats were weighed and recorded before starting the experiment, at the end of the third week, and before the animals were sacrificed at the last week, all at the same hour. By subtracting the remaining amount of food and water from the daily food and water amount, the amount of food and water consumed was calculated. These values were recorded for seven weeks. At the end of the seven weeks, the rats were sacrificed after blood specimens and tissues were taken.

RESULTS

Analyzing the changes in the food intake of each group within itself throughout the experiment, it was observed that there was an increase in the food intake in the control group; from the starting week to the last week, the food intake amount of the HFCS group began to decrease particularly after the second week; and it began to decrease after the third week in the groups that were administered probiotics and omega-3 fatty acids. The changes in the sacrifice weights in the HFCS + omega-3 fatty acid, HFCS + probiotic, and HFCS + probiotic + omega-3 fatty acid groups were found to be lower than that in the HFCS group. The maximum levels of glucose, ALT, ALP, serum cholesterol, triglyceride and AST were found to be in the HFCS group. It was determined that the minimum mean steatosis level was in the control group, while the maximum steatosis level was in the HFCS group.

CONCLUSIONS

As a result, there was a protective effect of probiotic and omega-3 fatty acid.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.