Probiotics Increase Intramuscular Fat and Improve the Composition of Fatty Acids in Sunit Sheep through the Adenosine 5'-Monophosphate-Activated Protein Kinase (AMPK) Signaling Pathway.

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, mRNA expression levels of genes related to lipid metabolism, and the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids. The inclusion of probiotics in the diet reduced the expression of adenosine 5'-monophosphate-activated protein kinase alpha 2 (AMPKα2) mRNA and carnitine palmitoyltransferase 1B (CPT1B) mRNA, while increasing the expression of acetyl-CoA carboxylase alpha (ACCα) mRNA, sterol regulatory element-binding protein-1c (SREBP-1c) mRNA, fatty acid synthase mRNA, and stearoyl-CoA desaturase 1 mRNA. The results of this study indicate that supplementation with probiotics can regulate fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.

Mechanism of Huangqisan Regulating Autophagy by AMPK/mTOR Signaling Pathway Against Hepatic Steatosis / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of Huangqisan （HQS） in regulating autophagy to alleviate hepatic steatosis and improve non-alcoholic fatty liver disease （NAFLD） based on adenosine 5'-monophosphate-activated protein kinase （AMPK）/mammalian target of rapamycin （mTOR） signaling pathway. MethodThe main chemical components and targets of HQS and NAFLD-related targets were collected from database and the intersection targets were used for Gene Ontology （GO） functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis. The protein-protein interaction （PPI） network was constructed， and in vivo experimental verification was conducted. Sixty C57BL/6J male mice were randomly divided into normal control group （NCD）， model group high-fat diet （HFD）， metformin group （MET， 0.25 g·kg-1）， low-dose Huangqisan group （HQS-L， 0.5 g·kg-1）， and the high-dose Huangqisan group （HQS-H， 1 g·kg-1）， with 12 mice in each group after a one-week acclimatization period. NAFLD model was induced by HFD， and intragastric administration was performed at the same time， once a day for 13 weeks. Random blood glucose， serum total cholesterol （TC）， triglyceride （TG）， non-esterified fatty acid （NEFA）， low density lipoprotein-chdesterol （LDL-C） levels， and liver TG content were determined. The liver weight was weighed， and liver index was calculated. Hematoxylin-eosin （HE） staining， oil red O staining， transmission electron microscope （TEM）， real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and Western blot were used to verify the effect and reveal the potential mechanism of C57BL/6J mice in vivo. ResultThrough network pharmacology analysis， combined with previous studies， it was predicted that HQS may improve NAFLD by regulating autophagy via the AMPK/mTOR signaling pathway. The result of in vivo experiment showed that， as compared with NCD group， random blood glucose， body weight， serum TC， LDL-C， NEFA， liver weight， liver index， and liver TG content of mice in the HFD groups were significantly increased （P<0.01）. HE staining showed massive lipid droplets （LDs） vacuolated， oil red O staining showed lipid accumulation in liver cells， and no obvious autophagosomes and autolysosome were observed under TEM. The relative mRNA expression of LC3A、LC3B、AMPKα1 and protein expression of AMPK， phosphory phosphorylated（p）-AMPK， and p-AMPK/AMPK were significantly down-regulated （P<0.01）， while the protein expression of microtubule-associated protein 1 light chain 3 （LC3）Ⅱ/Ⅰ and p-mTOR was significantly up-regulated （P<0.01）. As compared with HFD groups， liver weight， serum TG， and NEFA levels in HQS-L and HQS-H groups were significantly deceased （P<0.05， P<0.01）. HE staining and oil red O staining showed the improvement of liver pathological changes after HQS administration. Under TEM， a small amount of autophagosome and autolysosome were observed. Besides， liver index was significantly decreased in the HQS-L group （P<0.01）， and random blood glucose， serum TC level and liver TG content were significantly decreased in the HQS-H group （P<0.05）. The results of Western blot and Real-time PCR showed that the mRNA expression of LC3A and LC3B and the protein expression of LC3Ⅱ/Ⅰ， p-AMPK， and p-AMPK/AMPK were significantly up-regulated （P<0.01）， while the mRNA expressions of p62 and protein expression of p62 and p-mTOR were significantly down-regulated （P<0.05， P<0.01）. ConclusionHQS may promote autophagy and restore autophagy flux via the AMPK/mTOR signaling pathway to alleviate hepatic steatosis improving NAFLD.

Zhuanggu Zhitong Capsule alleviates postmenopausal osteoporosis in ovariectomized rats by regulating autophagy through AMPK/mTOR signaling pathway.

Background: Postmenopausal osteoporosis (PMOP) is the most common primary osteoporosis, which is prone to fractures and affect the health and quality of life of the elderly and even shorten their lifetime. Traditional Chinese medicine can not only effectively improve osteoporosis and reduce fracture rate, but also have tonifying and analgesic effects. The purpose of this study was to investigate the effects of Zhuanggu Zhitong (ZGZT) Capsule on autophagy related genes and proteins in PMOP rats, so as to elucidate the molecular mechanism of tonifying deficiency and regulating stasis in the treatment of osteoporosis and analgesia. Methods: The PMOP rat model was established by bilateral oophorectomy, and then the rats were randomly divided into control group, PMOP group, PMOP + ZGZT group and PMOP + E2 group. The changes of mechanical pain threshold of rats were detected by von Frey filaments, and the changes of mechanical pain threshold of rats in each group were compared. Computed tomography (CT) and dual-energy X-ray were used to measure the bone mineral density of lumbar bone tissue. Enzyme-linked immunosorbent assay (ELISA) and tartrate-resistant acid phosphatase (TRAP) staining were used to detect inflammatory factors and bone metabolism related indicators. Hematoxylin-eosin (HE) staining was used to observe the tissue morphology of lumbar vertebra tissue. Western blot (WB) and quantitative polymerase chain reaction (qPCR) were used to detect AMPK/mTOR pathway- and autophagy-related factor expression. Results: ZGZT can effectively restore the bone mineral density (BMD) of PMOP rats, improve the microstructure of lumbar vertebra of PMOP rats, restore the balance of bone metabolism, promote the expression of AMPK and autophagy related factors, inhibit the expression of mTOR and the release of inflammatory factors, and increase the mechanical pain threshold of PMOP rats, so as to effectively improve osteoporosis and relieving osteoporosis pain in PMOP rats. Conclusions: ZGZT affects autophagy by regulating AMPK/mTOR pathway, restores the homeostasis of bone metabolism and inhibits the release of inflammatory factors. Moreover, the regulation of feedback pathways between bone metabolism and inflammatory factors finally plays the role of "bone strengthening" and "pain relieving". ZGZT may be a new treatment for PMOP and relieving osteoporotic pain.

Oxidative stress induced by hydrogen peroxide promotes glycolysis by activating CaMKK/LKB1/AMPK pathway in broiler breast muscle.

Oxidative stress is common in the whole process of broiler production, and breast muscle is one of the target organs most vulnerable to oxidative attack. When broilers are subjected to oxidative stress, the regulation of adenosine 5-monophosphate activated protein kinase (AMPK) is a critical path to maintain the dynamic balance of intracellular energy. However, whether calcium/calmodulin-dependent protein kinase (CaMKK) and liver kinase B1 (LKB1) are involved in the regulation of AMPK activation in broiler breast muscle under oxidative stress has not been elucidated. In this study, a total of 144 one-day-old male Ross 308 chicks were selected, with an average body weight of 43.44 ± 0.04 g. The broilers were divided into 3 groups with 6 replicates of 8 broilers each (control group, intraperitoneal injection of physiological saline group, and intraperitoneal injection of hydrogen peroxide [H2O2] group), the injection time was selected on the 16th and 37th day of the experimental period, the injection volumes were 1.0 mL/kg broiler body weight. The results of this experiment showed that H2O2 exposure reduced the average daily gain (ADG) and increased the feed to gain ratio (F/G), the level of corticosterone (CORT) and the activity of lactate dehydrogenase (LDH) in serum were increased after H2O2 exposure. H2O2 exposure also increased the contents of reactive oxygen species (ROS) and protein carbonyl, but decreased the activities of catalase (CAT), total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in breast muscle. After H2O2 exposure, the activity of pyruvate dehydrogenase (PDH) was decreased, the content of glycogen was reduced, and the contents of adenosine monophosphate (AMP) and lactate were increased in breast muscle. In addition, H2O2 exposure increased the content of Ca2+, upregulated the protein expression levels of CaMKK1 and p-AMPK, and increased the activities of hexokinase (HK) and LDH in breast muscle. These findings suggested that the activation of CaMKK/LKB1/AMPK signaling pathway would be associated with the accelerated glycolysis of broiler breast muscle under oxidative stress.

Effect of Zuogui Jiangtang Tongmai Prescription on Astrocyte Injury by AGEs Combined with Oxygen-glucose Deprivation Based on AMPK/mTOR/ULK1 Pathway Related to Autophagy / 中国实验方剂学杂志

ObjectiveTo explore the effect and mechanism of Zuogui Jiangtang Tongmai prescription （ZGJTTMP） on astrocytes （ASs） injured by advanced glycation end products（AGEs） combined with oxygen-glucose deprivation （OGD）. MethodCell counting kit-8 （CCK-8） was used to determine the optimal concentration of AGEs and the action time of OGD， and the optimal blood concentration of ZGJTTMP was selected for follow-up experiments. ASs were divided into normal group， model group （AGEs + OGD）， ZGJTTMP group， an adenosine 5'-monophosphate-activated protein kinase （AMPK） inhibitor （Compound C） group， AMPK activator （AICAR） group， and combination group （ZGJTTMP + AICAR）. The morphological changes in ASs in each group were observed under an inverted microscope. The cell survival rate in each group was detected by CCK-8. The content of interleukin-1β（IL-1β）， interleukin-6（IL-6）， and tumor necrosis factor-α（TNF-α） was detected by enzyme-linked immunosorbent assay （ELISA）. The number of autophagosomes in each group was counted under an electron microscope. The expression of microtubule-associated protein light chain 3 （LC3） was observed by immunofluorescence. The protein expression of LC3， p62， p-AMPK， AMPK， p-mammalian target of rapamycin （mTOR）， mTOR， p-UNC-51 like kinase 1 （ULK1）， and ULK1 was detected by Western blot. ResultAccording to the results of cell survival rate， 200 mg·L-1 AGEs and OGD for 6 h were selected as the optimal modeling conditions for the model group， and 5% was selected as the optimal blood concentration of ZGJTTMP. Under the inverted microscope， the cells were severely damaged after modeling， but the cell injury in the ZGJTTMP group and the Compound C group was significantly improved. As revealed by ELISA results， the content of IL-1β， IL-6， and TNF-α in the model group increased （P<0.01）， and the content of inflammatory factors in the ZGJTTMP group and the Compound C group decreased （P<0.01）. Under the electron microscope， the number of autophagosomes in the model group increased significantly. The immunofluorescence results showed that the expression area of LC3 increased in the model group （P<0.01）， and the ZGJTTMP group and the Compound C group showed decreased number of autophagosomes and reduced expression area of LC3 （P<0.01）. As demonstrated by the results of Western blot， compared with the normal group， the model group showed increased expression of LC3Ⅱ/LC3Ⅰ and p-AMPK/AMPK （P<0.01） and decreased p62， p-mTOR/mTOR， and p-ULK1/ULK1 （P<0.01）. Compared with the model group， the ZGJTTMP group and the Compound C group showed decreased expression of LC3Ⅱ/LC3Ⅰ and p-AMPK/AMPK （P<0.01） and increased p62， p-mTOR/mTOR， and p-ULK1/ULK1 （P<0.01）. ConclusionZGJTTMP possesses a protective effect on ASs with inflammatory injury by AGEs combined with OGD， which may be achieved by inhibiting the activation of the AMPK/mTOR/ULK1 pathway related to autophagy， thus inhibiting the overexpression of autophagy.

Genipin and insulin combined treatment improves implant osseointegration in type 2 diabetic rats.

BACKGROUND: Type 2 diabetes mellitus (T2DM) has a harmful effect on the stability and osseointegration of dental implants. T2DM induces mitochondrial damage by inhibiting AMPK signaling, resulting in oxidative stress and poor osteogenesis in the peri-implant bone area. Genipin is a major component of gardenia fruits with strong antioxidant, anti-inflammation, and antidiabetic actions, and it also can activate mitochondrial quality control via the AMPK pathway. The purpose of this study was to investigate the effects of genipin and insulin treatment on implant osseointegration in T2DM rats and explore the underlying mechanisms. METHODS: Streptozotocin-induced diabetic rats received implant surgery in their femurs and were then assigned to five groups that were subjected to different treatments for three months: control group, T2DM group, insulin-treated T2DM group (10 IU/kg), genipin-treated T2DM group (50 mg/kg), and the genipin and insulin combination-treated T2DM group. Then, we regularly assessed the weight and glucose levels of the animals. Rats were euthanized at 3 months after the implantation procedure, and the femora were harvested for microscopic computerized tomography analysis, biomechanical tests, and different histomorphometric assessment. RESULTS: The results indicated that the highest blood glucose and oxidative stress levels were measured for the T2DM group, resulting in the poorest osseointegration. The combination-treated T2DM group mitigated hyperglycemia and normalized, reactivated AMPK signaling, and alleviated oxidative stress as well as reversed the negative effect of osseointegration. There were beneficial changes observed in the T2DM-genipin and T2DM-insulin groups, but these were less in comparison to the combination treatment group. CONCLUSION: Our study suggests that treatment with genipin in combination with insulin could be an effective method for promoting implant osseointegration in T2DM rats, which may be related to AMPK signaling.

The Study of the Response of Fat Metabolism to Long-Term Energy Stress Based on Serum, Fatty Acid and Transcriptome Profiles in Yaks.

Long-term energy stress (ES) during the cold season is a serious problem for the breeding of yaks. In this paper, the response of fat metabolism in yaks to long-term ES during the cold season was studied. Gas chromatography (GC) analysis showed that the percentage of saturated fatty acids (SFAs) in the subcutaneous fat of the yaks in the ES group was 42.7%, which was less than the 56.6% in the CO group (p < 0.01) and the percentage of polyunsaturated unsaturated fatty acids (PUFAs) in the subcutaneous fat of the yaks in the ES group was 38.3%, which was more than the 26.0% in the CO group (p < 0.01). The serum analysis showed that fatty acid oxidation in yaks was increased under long-term ES. In the subcutaneous fat of yaks under long-term ES, the gene expression levels of glycerol-3-phosphate acyltransferase 4 (GPAT4), hormone-sensitive lipase (HSL), patatin-like phospholipase domain-containing protein 2 (PNPLA2), acyl-CoA dehydrogenase (ACAD), acyl-coenzyme A thioesterase 8 (ACOT8), facilitated glucose transporter (GLUT4), 3-oxoacyl-[acyl-carrier-protein] synthase (OXSM), oestradiol 17-beta-dehydrogenase 8 (HSD17B8) and malonate-Co-A ligase ACSF3 (ACSF3) were downregulated (q < 0.05), whereas the gene expression levels of aquaporin-7 (AQP7), long-chain-fatty-acid-CoA ligase (ACSL), elongation of very long chain fatty acids protein (ELOVL) and fatty acid desaturase 1 (FADS1) were upregulated (q < 0.05), indicating the inhibition of fat catabolism, fat anabolism, fatty acid oxidation, glucose (GLU) intake and SFA synthesis and the promotion of glycerinum (GLY) transportation and PUFA synthesis. Additional findings showed that the gene expression levels of leptin (LEP), adenosine 5'-monophosphate-activated protein kinase (AMPK) and phosphatidylinositol 3-kinase (PI3K) were upregulated (q < 0.05), whereas the gene expression levels of malonyl-CoA decarboxylase (MCD), sterol regulatory element-binding protein 1 (SREBF1), mammalian target of rapamycin (mTOR) and serine/threonine-protein kinase (AKT) were downregulated (q < 0.05), indicating that fat metabolism in the subcutaneous fat of yaks under ES was mainly regulated by AMPK signaling and mTOR and PI3K-AKT signaling were also involved. Energy consumption was inhibited in the subcutaneous fat itself. This study can provide a theoretical basis for the healthy breeding and genetic breeding of yaks.

Rosiglitazone promotes phosphorylation of AMPK protein and improves insulin resistance in db/db mice / 上海预防医学

Objective To observe the effect of rosiglitazone on the protein expression of AMPK and GLUT4 in peripheral tissue (liver, skeletal muscle and fat) of type 2 diabetic db/db mice and to prove that rosiglitazone can regulate the glucose metabolism in db/db mice partly through the AMPK pathway. Methods db/db mice were randomly divided into model group and rosiglitazone group according to their blood glucose.The db/m mice were normal control group.After 4 weeks of administration, fasting blood glucose was detected in each group.Western blot was used to detect the contents of AMPK, p-AMPK and GLUT4 in liver, skeletal muscle and adipose tissue. Results (1) Rosiglitazone significantly reduced the fasting blood glucose of db/db mice; (2)Rosiglitazone increased the level of AMPK phosphorylation in the liver, skeletal muscle and adipose tissue of db/db mice, and increased the content of GLUT4 protein in skeletal muscle and adipose tissue. Conclusion Rosiglitazone can increase the phosphorylation of AMPK and the expression of GLUT4 protein in the liver, muscle and fat tissue of db/db mice, and promote the uptake and utilization of glucose in peripheral tissue, suggesting that it can regulate glucose metabolism in db/db mice partly through the AMPK pathway.