The aim of the present study was to investigate the effects of short-term ketogenic diet on the low temperature tolerance of mice and the involvement of peroxisome proliferator-activated receptor α (PPARα). C57BL/6J mice were divided into two groups: normal diet (WT+ND) group and ketogenic diet (WT+KD) group. After being fed with normal or ketogenic diet at room temperature for 2 d, the mice were exposed to 4 °C low temperature for 12 h. The changes in core temperature, blood glucose, blood pressure of mice under low temperature condition were detected, and the protein expression levels of PPARα and mitochondrial uncoupling protein 1 (UCP1) were detected by Western blot. PPARα knockout mice were divided into normal diet (PPARα^-/-+ND) group and ketogenic diet (PPARα^-/-+KD) group. After being fed with the normal or ketogenic diet at room temperature for 2 d, the mice were exposed to 4 °C low temperature for 12 h. The above indicators were also detected. The results showed that, at room temperature, the protein expression levels of PPARα and UCP1 in liver and brown adipose tissue of WT+KD group were significantly up-regulated, compared with those of WT+ND group. Under low temperature condition, compared with WT+ND, the core temperature and blood glucose of WT+KD group were increased, while mean arterial pressure was decreased; The ketogenic diet up-regulated PPARα protein expression in brown adipose tissue, as well as UCP1 protein expression in liver and brown adipose tissue of WT+KD group. Under low temperature condition, compared to WT+ND group, PPARα^-/-+ND group exhibited decreased core temperature and down-regulated PPARα and UCP1 protein expression levels in liver, skeletal muscle, white and brown adipose tissue. Compared to the PPARα^-/-+ND group, the PPARα^-/-+KD group exhibited decreased core temperature and did not show any difference in the protein expression of UCP1 in liver, skeletal muscle, white and brown adipose tissue. These results suggest that the ketogenic diet promotes UCP1 expression by up-regulating PPARα, thus improving low temperature tolerance of mice. Therefore, short-term ketogenic diet can be used as a potential intervention to improve the low temperature tolerance.
Animals ; Mice ; Adipose Tissue, Brown/metabolism* ; PPAR alpha/pharmacology* ; Diet, Ketogenic ; Uncoupling Protein 1/metabolism* ; Blood Glucose/metabolism* ; Temperature ; Mice, Inbred C57BL ; Liver ; Adipose Tissue/metabolism*

OBJECTIVE: In this study, the combined effect of two stressors, namely, electromagnetic fields (EMFs) from mobile phones and fructose consumption, on hypothalamic and hepatic master metabolic regulators of the AMPK/SIRT1-UCP2/FOXO1 pathway were elucidated to delineate the underlying molecular mechanisms of insulin resistance. METHODS: Weaned Wistar rats (28 days old) were divided into 4 groups: Normal, Exposure Only (ExpO), Fructose Only (FruO), and Exposure and Fructose (EF). Each group was provided standard laboratory chow ad libitum for 8 weeks . Additionally, the control groups, namely, the Normal and FruO groups, had unrestricted access to drinking water and fructose solution (15%), respectively. Furthermore, the respective treatment groups, namely, the ExpO and EF groups, received EMF exposure (1,760 MHz, 2 h/day x 8 weeks). In early adulthood, mitochondrial function, insulin receptor signaling, and oxidative stress signals in hypothalamic and hepatic tissues were assessed using western blotting and biochemical analysis. RESULT: In the hypothalamic tissue of EF, SIRT1, FOXO 1, p-PI3K, p-AKT, Complex III, UCP2, MnSOD, and catalase expressions and OXPHOS and GSH activities were significantly decreased ( P < 0.05) compared to the Normal, ExpO, and FruO groups. In hepatic tissue of EF, the p-AMPKα, SIRT1, FOXO1, IRS1, p-PI3K, Complex I, II, III, IV, V, UCP2, and MnSOD expressions and the activity of OXPHOS, SOD, catalase, and GSH were significantly reduced compared to the Normal group ( P < 0.05). CONCLUSION The findings suggest that the combination of EMF exposure and fructose consumption during childhood and adolescence in Wistar rats disrupts the closely interlinked and multi-regulated crosstalk of insulin receptor signals, mitochondrial OXPHOS, and the antioxidant defense system in the hypothalamus and liver.
Humans ; Rats ; Animals ; Adult ; Rats, Wistar ; Fructose/metabolism* ; Catalase ; Receptor, Insulin/metabolism* ; AMP-Activated Protein Kinases/metabolism* ; Electromagnetic Fields/adverse effects* ; Sirtuin 1/metabolism* ; Cell Phone ; Phosphatidylinositol 3-Kinases/metabolism* ; Forkhead Box Protein O1/metabolism* ; Uncoupling Protein 2

OBJECTIVETo evaluate the effect of bone morphogenetic protein(BMP7)on the differentiation of adipose derived mesenchymal stem cells(AD-MSCs)isolated from different adipose tissues into brown adipocytes in rats.

METHODSPrimary AD-MSCs were isolated from rate interscapular brown adipose tissue(iBAT),inguinal subcutaneous white adipose tissue(sWAT),and epididymal white adipose tissue(eWAT),respectively,and then cultivated in vitro. Differentiation of AD-MSCs into brown adipocytes was induced by BMP7. The characteristics of brown adipocytes were detected by immunofluorescence staining and oil red staining of cells. The expression levels of brown adipocyte-related genes were detected by polymerase chain reaction.

RESULTSAD-MSCs from iBAT and sWAT were differentiated into cluster multilocular cells,which were stained red by oil red "O"staining and showed uncoupling protein 1-positive by immunofluorescent staining method. AD-MSCs from eWAT had a small number of scattered multilocular cells and showed uncoupling protein 1-negative. The results of reverse transcription-polymerase chain reaction showed that the uncoupling protein 1 gene was highly expressed in the iBAT group and sWAT group but was negative in the eWAT group.

CONCLUSIONAD-MSCs isolated from different adipose tissues in rats have different gene expression profiles and differentiation potentials.

Adipocytes, Brown ; physiology ; Adipose Tissue ; metabolism ; Adipose Tissue, Brown ; physiology ; Animals ; Bone Morphogenetic Protein 7 ; metabolism ; Cell Differentiation ; physiology ; Ion Channels ; metabolism ; Mesenchymal Stromal Cells ; physiology ; Mitochondrial Proteins ; metabolism ; Obesity ; metabolism ; Rats ; Uncoupling Protein 1

OBJECTIVETo investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome.

METHODSThe perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein β(CEBPβ), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA).

RESULTSThe mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPβ, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ.

CONCLUSIONThe expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.

Adrenalectomy ; Adrenocorticotropic Hormone ; CCAAT-Enhancer-Binding Protein-beta ; metabolism ; Cushing Syndrome ; metabolism ; surgery ; Early Growth Response Protein 1 ; metabolism ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; metabolism ; Real-Time Polymerase Chain Reaction ; Subcutaneous Fat ; metabolism ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Uncoupling Protein 1 ; metabolism

OBJECTIVETo observe the expression of SIRT1 and mitochondrial uncoupling protein 2 (UCP2) in the liver of rats with type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver (NAFLD) and explore the possible pathogenesis of T2DM and NAFLD.

METHODSTwenty-four male SD rat were randomized equally into control group and T2DM and NAFLD group (MC group), fed with standard diet and high-fat and high-sugar diet, respectively. At 12 weeks, the rats in MC group received a single dose of STZ (30 mg/kg) injected into the abdominal cavity for pancreatic islet destruction, and those in the control group received an equivalent volume of citric acid buffer. At 14 weeks, the body weight, FBG, hepatic function, blood lipid levels, FFAs, FINs and HOMA-IR of the rats were measured, and the liver pathology was examined with HE staining. The expression of SIRT1 and UCP2 in the rat liver was detected by immunohistochemistry and real-time quantitative PCR.

RESULTSAt 14 weeks, FBG, ALT, AST, TC, TG, LDL-C, VLDL, FFAs, FINs and HOMA-IR were significantly higher and HDL-C was significantly lower in MC group than in the control group (P<0.05). Pathological examination showed good structural integrity of the liver in the control group, and the liver cells were closely arranged with rich cytoplasm and round cell nuclei; in MC group, moderate to severe fatty liver was detected, and the liver cells showed severe ballooning degeneration and contained lipid vacuoles in the cytoplasm. The expression of SIRT1 was significantly lower and UCP2 significantly higher in MC group than in the control group (P<0.05).

CONCLUSIONThe expression of SIRT1 is significantly lowered and UCP2 increased in the liver of rats with T2DM and NAFLD.

Animals ; Diabetes Mellitus, Type 2 ; complications ; metabolism ; Fatty Liver ; complications ; metabolism ; Ion Channels ; metabolism ; Liver ; metabolism ; Male ; Mitochondrial Proteins ; metabolism ; Non-alcoholic Fatty Liver Disease ; Rats ; Rats, Sprague-Dawley ; Sirtuin 1 ; metabolism ; Uncoupling Protein 2

To reveal the roles of uncoupling proteins (UCPs) in disorder of mitochondrial oxidative phosphorylation induced by free fatty acid during hypoxic exposure, the effects of palmitic acid on activity of UCPs, proton leak and mitochondrial membrane potential in hypoxia-exposed rat brain mitochondria were observed in vitro. Adult Sprague-Dawley (SD) rats were set randomly into control, acute hypoxia and chronic hypoxia groups (n=8 in each group). The acute and chronic hypoxic rats were exposed to simulated 5000 m high altitude in a hypobaric chamber 23 h/d for 3 d and 30 d, respectively. The brain mitochondria were isolated by centrifugation. UCP content and activity were detected by [(3)H]-GTP binding method. The proton leak was measured by TPMP(+) electrode and oxygen electrode. The membrane potential of mitochondria was calculated by detecting the fluorescence from Rodamine 123. Hypoxic exposure resulted in an increase in UCP activity and content as well as proton leak, but a decrease in the membrane potential of rat brain mitochondria. Palmitic acid resulted in further increases in UCP activity and content as well as proton leak, and further decrease in membrane potential of brain mitochondria in vitro from hypoxia-exposed rats, but hypoxic exposure decreased the reactivity of cerebral mitochondria to palmitic acid, especially in the acute hypoxia group. There was a negative correlation between mitochondrial proton leak and K(d) value (representing derivative of UCP activity, P<0.01, r = -0.906), and a positive correlation between proton leak and B(max) (representing the maximal content of UCPs in mitochondrial inner membrane, P<0.01, r = 0.856). Cerebral mitochondrial membrane potential was negatively correlated with proton leak (P<0.01, r = -0.880). It is suggested that hypoxia-induced proton leak enhancement and membrane potential decrease are correlated with the increased activity of UCPs. Hypoxia can also decrease the sensitivity of cerebral mitochondria to palmitic acid, which may be a self-protective mechanism in high altitude environment.
Altitude ; Animals ; Brain ; metabolism ; Cell Hypoxia ; Ion Channels ; metabolism ; Membrane Potential, Mitochondrial ; Mitochondria ; metabolism ; Mitochondrial Proteins ; metabolism ; Oxidative Phosphorylation ; Oxygen ; metabolism ; Palmitic Acid ; pharmacology ; Protons ; Rats ; Rats, Sprague-Dawley ; Uncoupling Protein 1

AIMTo investigate the effect of cold stress on the energy metabolism in Yisha chickens.

METHODSMale Yisha chickens were subjected to acute (0.25, 1, 3, 6, 12 and 24 h) and chronic (5, 10 and 20 d) cold stress (12 +/- 1 degrees C). This study detected uncoupling protein (UCP) mRNA levels in gastrocnemius, glucagons (GLU) content in blood plasma and insulin (INS), blood glucose (BG) and free fatty acid (FFA) content in serum in the chicken.

RESULTSThe results were as follow: with the time lapsing during acute cold stress, UCP mRNA levels gradually increased, the content of INS and FFA showed fluctuant change, GLU content gradually increased, and BG content first increased and then decreased. During chronic cold stress, UCP mRNA levels significantly increased compared with their control group at every stress time point, and the content of INS, GLU, BG and FFA were all gradually increased with the time lapsing.

CONCLUSIONCold stress could change the energy metabolism in chickens. And the different extent cold stress would produce different effects on the energy metabolism.

Animals ; Chickens ; Cold Temperature ; Energy Metabolism ; physiology ; Fatty Acids, Nonesterified ; blood ; Insulin ; blood ; Ion Channels ; genetics ; metabolism ; Male ; Mitochondrial Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Stress, Physiological ; physiology ; Uncoupling Protein 1

OBJECTIVETo investigate activation of brown adipose tissue (BAT) stimulated by medium-chain triglyceride (MCT).

METHODS30 Male C57BL/6J obese mice induced by fed high fat diet (HFD) were divided into 2 groups, and fed another HFD with 2% MCT or long-chain triglyceride (LCT) respectively for 12 weeks. Body weight, blood biochemical variables, interscapular brown fat tissue (IBAT) mass, expressions of mRNA and protein of beta 3-adrenergic receptors (β3-AR), uncoupling protein-1 (UCP1), hormone sensitive lipase (HSL), protein kinase A (PKA), and adipose triglyceride lipase (ATGL) in IBAT were measured.

RESULTSSignificant decrease in body weight and body fat mass was observed in MCT group as compared with LCT group (P<0.05) after 12 weeks. Greater increases in IBAT mass was observed in MCT group than in LCT group (P<0.05). Blood TG, TC, LDL-C in MCT group were decreased significantly, meanwhile blood HDL-C, ratio of HDL-C/LDL-C and norepinephrine were increased markedly. Expressions of mRNA and protein of β3-AR, UCP1, PKA, HSL, ATGL in BAT were greater in MCT group than in LCT group (P<0.05).

CONCLUSIONOur results suggest that MCT stimulated the activation of BAT, possible via norepinephrine pathway, which might partially contribute to reduction of the body fat mass in obese mice fed high fat diet.

Adipose Tissue, Brown ; drug effects ; Adiposity ; drug effects ; Animals ; Dietary Fats ; administration & dosage ; pharmacology ; Ion Channels ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mitochondrial Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Triglycerides ; chemistry ; pharmacology ; Uncoupling Protein 1 ; Weight Loss

Mulberry (Morus alba L.) leaf is a well-established traditional Chinese botanical and culinary resource. It has found widespread application in the management of diabetes. The bioactive constituents of mulberry leaf, specifically mulberry leaf flavonoids (MLFs), exhibit pronounced potential in the amelioration of type 2 diabetes (T2D). This potential is attributed to their ability to safeguard pancreatic β cells, enhance insulin resistance, and inhibit α-glucosidase activity. Our antecedent research findings underscore the substantial therapeutic efficacy of MLFs in treating T2D. However, the precise mechanistic underpinnings of MLF's anti-T2D effects remain the subject of inquiry. Activation of brown/beige adipocytes is a novel and promising strategy for T2D treatment. In the present study, our primary objective was to elucidate the impact of MLFs on adipose tissue browning in db/db mice and 3T3-L1 cells and elucidate its underlying mechanism. The results manifested that MLFs reduced body weight and food intake, alleviated hepatic steatosis, improved insulin sensitivity, and increased lipolysis and thermogenesis in db/db mice. Moreover, MLFs activated brown adipose tissue (BAT) and induced the browning of inguinal white adipose tissue (IWAT) and 3T3-L1 adipocytes by increasing the expressions of brown adipocyte marker genes and proteins such as uncoupling protein 1 (UCP1) and beige adipocyte marker genes such as transmembrane protein 26 (Tmem26), thereby promoting mitochondrial biogenesis. Mechanistically, MLFs facilitated the activation of BAT and the induction of WAT browning to ameliorate T2D primarily through the activation of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling pathway. These findings highlight the unique capacity of MLF to counteract T2D by enhancing BAT activation and inducing browning of IWAT, thereby ameliorating glucose and lipid metabolism disorders. As such, MLFs emerge as a prospective and innovative browning agent for the treatment of T2D.
Mice ; Animals ; Adipose Tissue, Brown ; Sirtuin 1/pharmacology* ; Diabetes Mellitus, Type 2/metabolism* ; AMP-Activated Protein Kinases/metabolism* ; Morus/metabolism* ; Flavonoids/metabolism* ; Prospective Studies ; Signal Transduction ; Adipose Tissue, White ; Plant Leaves ; Uncoupling Protein 1/metabolism* ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism*

The inducible co-activator PGC-1α plays a crucial role in adaptive thermogenesis and increases energy expenditure in brown adipose tissue (BAT). Meanwhile, chronic inflammation caused by infiltrated-macrophage in the white adipose tissue (WAT) is a target for the treatment of obesity. Bofutsushosan (BF), a traditional Chinese medicine composed of 17 crude drugs, has been widely used to treat obesity in China, Japan, and other Asia countries. However, the mechanism underlying anti-obesity remains to be elucidated. In the present study, we demonstrated that BF oral administration reduced the body weight of obese mice induced by high-fat diet (HFD) and alleviated the level of biochemical markers (P < 0.05), including blood glucose (Glu), total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL-C) and insulin. Our further results also indicated that oral BF administration increased the expression of PGC-1α and UCP1 in BAT. Moreover, BF also reduced the expression of inflammatory cytokines in WAT, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These findings suggested that the mechanism of BF against obesity was at least partially through increasing gene expression of PGC-1α and UCP1 for energy consumption in BAT and inhibiting inflammation in WAT.
Adipose Tissue, Brown ; drug effects ; immunology ; Adipose Tissue, White ; drug effects ; immunology ; Animals ; Cytokines ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Energy Metabolism ; drug effects ; Female ; Humans ; Interleukin-6 ; genetics ; immunology ; Mice ; Obesity ; drug therapy ; genetics ; immunology ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; genetics ; immunology ; Tumor Necrosis Factor-alpha ; genetics ; immunology ; Uncoupling Protein 1 ; genetics ; metabolism