Efecto de extractos de frutas y hortalizas en la incorporación de glucosa en células musculares in vitro / Effect of fruit and vegetable extracts on the incorporation of glucose in muscle cells "in vitro"

Skeletal muscle appears to play a central role in the development of insulin resistance (IR) and consequently the metabolic syndrome due to high-fat diets, obesity, and aging. Recent evidence suggests that some bioactive compounds present in natural products can affect blood glucose, possibly due to interactions between the compounds and glucose transporters. As an objective, to evaluate the effect of the extract of the green bean (PV, Phaseolus vulgaris) and apple of small fruit of thinning (Malus domestica, MAF and MIT extracts) on the incorporation of glucose in C2C12 muscle cells. For this, the cytotoxic effect of the extracts on the cells was determined by detecting formazan. Subsequently, glucose incorporation was determined using a fluorescent glucose analog in cells treated with the extracts. Finally, the effect of the extracts on IL-6 and TNFα production was evaluated by ELISA. Results: PV and MAF decreased 50% of viability at 1000µg / mL while MIT only decreased 10% at that concentration. PV had no significant effect on glucose incorporation and the MAF and MIT extract extracts significantly increased glucose incorporation at 100 µg / mL (13500 and 18000 URF respectively). PV increases the secretion of IL-6 and TNF-α, MAF and MIT only increase the expression of IL-6. Conclusion: These results make it possible to establish natural extracts derived from thinning small fruit apple can be used as a possible treatment for pathologies with high blood glucose levels.

Effects of laser stimulation with different power on oxygen consumption rate of CC myoblasts in mice / 中国应用生理学杂志

OBJECTIVE@#To investigate the effects of 650 nm laser irradiation on cell oxygen consumption rate in CC myoblasts following different doses.@*METHODS@#CC cells were irradiated with 650 nm laser(λ=650 nm, p=5 mW) with energy densities of 0, 0.4, and 0.8 J/cm. Cell oxidative function was measured by oxygen consumption rate kit. Protein expression of myogenic determination factor (MyoD), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), mammalian target of rapamycin (mTOR) and its phosphorylation were detected by Western blot.@*RESULTS@#Compared to the control group, the expression levels of MyoD, PGC-1α protein were increased and cell oxygen consumption rate was promoted in the low dose group(<0.05). MyoD and PGC-1α protein expressions were also increased(<0.05), the ratio of mTOR and its phosphorylationwere decreased significantly in the high dose group(<0.05).@*CONCLUSIONS@#650 nm laser irradiation that dose is 0.4 J/cm enhances cell oxidative function, it related to that proper dose laser irradiation promoted the expression of PGC-1a protein.

The Stimulatory Effect of Essential Fatty Acids on Glucose Uptake Involves Both Akt and AMPK Activation in C2C12 Skeletal Muscle Cells

Essential fatty acid (EFA) is known to be required for the body to function normally and healthily. However, the effect of EFA on glucose uptake in skeletal muscle has not yet been fully investigated. In this study, we examined the effect of two EFAs, linoleic acid (LA) and alpha-linolenic acid (ALA), on glucose uptake of C2C12 skeletal muscle cells and investigated the mechanism underlying the stimulatory effect of polyunsaturated EFAs in comparison with monounsaturated oleic acid (OA). In palmitic acid (PA)-induced insulin resistant cells, the co-treatment of EFAs and OA with PA almost restored the PA-induced decrease in the basal and insulin-stimulated 2-NBDG (fluorescent D-glucose analogue) uptake, respectively. Two EFAs and OA significantly protected PA-induced suppression of insulin signaling, respectively, which was confirmed by the increased levels of Akt phosphorylation and serine/threonine kinases (PKCtheta and JNK) dephosphorylation in the western blot analysis. In PA-untreated, control cells, the treatment of 500 microM EFA significantly stimulated 2-NBDG uptake, whereas OA did not. Phosphorylation of AMP-activated protein kinase (AMPK) and one of its downstream molecules, acetyl-CoA carboxylase (ACC) was markedly induced by EFA, but not OA. In addition, EFA-stimulated 2-NBDG uptake was significantly inhibited by the pre-treatment of a specific AMPK inhibitor, adenine 9-beta-D-arabinofuranoside (araA). These data suggest that the restoration of suppressed insulin signaling at PA-induced insulin resistant condition and AMPK activation are involved at least in the stimulatory effect of EFA on glucose uptake in C2C12 skeletal muscle cells.

Effects of myostatin propeptide gene tranfection on glucose metabolism in cultured C2C12 cells / 中华内分泌代谢杂志

Objective To investigate the effects of recombinant adeno-associated virus-mediated myostatin propeptide (MPRO) on uptake and oxidation of glucose,and glycogen synthesis in C2C12 myotubes,as well as the associated molecular mechanism.Methods Mature C2C12 myotubes were assigned to the following 6 groups:control,insulin,green fluorescent protein (GFP),insulin + GFP,MPRO,and insulin + MPRO groups.Glucose uptake,glucose oxidation,and glycogen synthesis were detected by counting radioactivity of 14CO2 or 14C labeled glycogen derived from 2-deoxy-[1-14 C] glucose.The activity of insulin signal pathway was evaluated by Western blot.Results Compared with control group,glucose uptake and glycogen synthesis were significantly increased in insulin and insulin+GFP groups,and further increased in insulin+MPRO group as compared with insulin alone(all P＜ O.05).However,MPRO and insulin had no effect on glucose oxidation.The phosphorylations of insulin receptor (IR) β,insulin receptor substrate 1 (IRS-1),protein kinase B (Akt),glycogen synthase kinase-3 β (GSK-3β),and the expressions of phosphatidylinositol 3-kinase (PI3K) and glucose transporter 4 (Glut4) in membrane were significantly increased in insulin and insulin+GFP groups compared with control group(all P＜0.05),and were further increased after MPRO transfection (all P ＜ 0.05).Conclusion MPRO may increase insulin-stimulated glucose uptake and glycogen synthesis in C2C12 cells by activating the IRS/PI3K/Akt signal pathway.

miR-376b-3p promotes Runx2-induced early osteogenic differentiation of C2C12 cells / 中国组织工程研究

BACKGROUND: The transcription factor Runx2 is the key factor that regulates osteogenic differention and bone development. It has been reported that the C2C12 mesenchymal cells can be induced to differentiate into osteoblasts by Runx2 overexpression, but the molecular mechanism of induction is stil largely unclear. OBJECTIVE: To investigate the role of the members of the miR-376 family during Runx2-induced osteogenic differentiation in C2C12 cells. METHODS: The expression of the members of the miR-376 family was detected by real-time quantitative PCR at different time points using C2C12/Runx2Dox sub-line with conditional Runx2 expression. In miR-376b-3p-transfected C2C12/Runx2Dox cells, the expression of osteoblast markers, such as alkaline phosphatase and osteocalcin, was detected by real-time quantitative PCR, and the alkaline phosphatase activity was also examined by alkaline phosphatase staining. The putative miR-376b-3p targets were commonly predicted by online tools (miRanda, miRWalk and TargetScan). The functional classification of these putative targets was performed by DAVID Bioinformatics Resources database. RESULTS AND CONCLUSION: The expression of miR-376b-3p was significantly increased during Runx2-induced osteogenic differentiation of C2C12 cells, but the expression of other members was not changed. Transfection of miR-376b-3p mimic upregulated alkaline phosphatase expression, but had no effect on osteocalcin expression. The alkaline phosphatase activity was also increased by transfection of miR-376b-3p. The functional classification of miR-376b-3p putative targets showed that miR-376b-3p is involved in the skeleton development, indicating the role of miR-376b-3p in osteoblast differentiation. Taken together, these results suggest that Runx2 promotes early osteogenic differentiation in C2C12 cells by regulating the expression of genes related to osteogenic differentiation through upregulation of miR-376b-3p.

Depletion of Mitochondrial DNA Stabilizes C1qTNF-Related Protein 6 mRNA in Muscle Cells

Mutation and reduction of mitochondrial DNA (mtDNA) have been suggested as factors in the pathogenesis of several metabolic diseases. Recently, we demonstrated that C1qTNF-related protein-6 (CTRP6) is involved in fatty acid metabolism in muscle cells. In this study, we showed that expression of CTRP6 was up-regulated in mtDNA-depleted C2C12 cells, which displayed a marked decrease in cellular mtDNA and ATP content. Replacement of mtDNA normalized the expression level of CTRP6 similar to that in normal C2C12 cells, indicating that CTRP6 expression was up-regulated by mtDNA depletion. However, CTRP6 promoter activity remained unchanged in mtDNA-depleted cells. We also found that mtDNA depletion inhibited decay of CTRP6 mRNA. Taken together, mtDNA depletion induces an increase in CTRP6 expression by increasing mRNA stability.

No effect of low-level lasers on in vitro myoblast culture.

Effects of phototherapy using low-level lasers depend on irradiation parameters and the type of laser used. The aim of the present study was to evaluate the effect of phototherapy on the proliferation of cultured C2C12 myoblasts under different nutritional conditions using low-level GaAlAs and InGaAlP lasers with different parameters and incubation periods. C2C12 cells cultured in regular and nutrient-deficient medium were irradiated with low-level GaAlAs (780 nm) and InGaAlP (660 nm) lasers with energy densities of 3.8, 6.3 and 10 J/cm2, and 3.8, 10 and 17.5 J/cm2, respectively. Cell proliferation was assessed 48 and 72 h after irradiation by MTT assay. There were no significant differences in cell proliferation between laser-treated myoblasts and control cultures for any of the parameters and incubation periods. Further studies are necessary to determine the correct laser parameters for optimizing the biostimulation of myoblasts.

Expression and functional study of human recombinant chemokine-like factor I in Drosophila S2 cells / 中华微生物学和免疫学杂志

Objective To express human chemokine-like factor 1 (CKLF1) in Drosophila S2 cells and study its function. Methods The pMT/V5-His-CKLF1 expression plasmid was constructed and transfected into Drosophila S2 cells. The positive clones were selected through PCR and RT-PCR. The culture medium was analyzed by Western blot with anti-CKLF1 polyclonal antibody. Chemotaxis and MTT assays on human peripheral blood and C2C12 cells, respectively, were then carried out with the medium. Results CKLF1 was transcribed efficiently in S2 cells. The expressed CKLF1 protein could be detected in the culture supernatant by Western blot, which showed weak chemotactic activity on both human peripheral blood neutrophils and lymphocytes as well as enhancing effect on the proliferation of C2C12 cells. Conclusion CKLF1 was expressed successfully in Drosophila S2 cells and secreted into the culture medium. The recombinant CKLF1 expressed in Drosophila cells can chemoattract leucocytes and promote the proliferation of C2C12 cells.

Hypoxia enhanced proliferation of C_2C_(12) cells and its possible mechanism / 医学研究生学报

Objective:To explore the role of hypoxia in C_2C_(12) cells proliferation.Methods:We chose 10% oxygen concentration.Cell numbers were counted with a hemacytometer.The proliferous indexes were observed with a flow cytometer.HIF-1? protein was determined by Western blot,mRNA expression was determined with reverse transcriptase-polymerase chain reaction(RT-PCR).Results:The cell numbers and proliferous indexes were higher(P