Effectiveness of sub-maximal intermittent exercise on muscle glycogen depletion, PGC-1<i>α</i>and PDK-4 gene expression

Several metabolic gene expressions are regulated in concert with muscle glycogen status. We hypothesized that intermittent exercise performed at high but sub-maximal intensities with long recovery periods would induce a low glycogen state that would stimul- ate peroxisome proliferator-activated receptor-γ coa- ctivator-1α (PGC1-α) and pyruvate dehydrogenase kinase-4 (PDK-4) gene expression in muscle. Nine young human subjects performed two intermittent exercise sessions. One session consisted of 60 s cycling bouts at VO2max (IE100%), and the other session consisted of 75 s cycling bouts at 80% VO2max (IE80%). Twelve bouts of exercise were completed in both sessions with a 4 min rest between each bout. Muscle specimens were obtained at pre-exercise and immediately, 1.5 h and 3 h post-exercise. Muscle gly- cogen was significantly decreased after both sessions (IE100%, 94.1 ± 5.8 to 38.7 ± 5.5 mmol/kg w.w.;IE80%, 94.6 ± 9.1 to 53.3 ± 4.8 mmol/kg w.w.;both P α and PDK- 4 mRNA expression were significantly increased after exercise in both IE100% and IE80% (PGC-1α: ~3.7 and ~2.9-fold, respectively;PDK-4: ~11.1 and ~3.5-fold, respectively;all P 100% than in IE80% (P a and PDK-4 mRNA expression, suggesting that increasing exercise intensity contributes to muscle glycogen depletion and PDK-4 mRNA expression in human skeletal muscle.

Pioglitazone attenuates the severity of sodium taurocholate-induced severe acute pancreatitis

AIM： To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-γ, （PPARγ） ligand, on development of severe acute pancreatitis （SAP） and expression of nuclear factor-kappa B （NF-κB） and intercellular adhesion molecule-1 （ICAM-1） in the pancreas. METHODS： Male Sprague-Dawley （SD） rats （160-200 g） were randomly allocated into three groups （n = 18 in each group）： severe acute pancreatitis group, pioglitazone group, sham group. SAP was induced by retrograde infusion of 1 mL/kg body weight 5% sodium taurocholate （STC） into the biliopancreatic duct of male SD rats. Pioglitazone was injected intraperitoneally two hours piror to STC infusion. Blood and ascites were obtained for detecting amylase and ascitic capacity. Pancreatic wet/dry weight ratio, expression of NF-κB and ICAM-1 in pancreatic tissues were detected by immunohistochemical staining. Pancreatic tissue samples were stained with hematoxylin and eosin （HE） for routine optic microscopy. RESULTS： Sham group displayed normal pancreatic structure. SAP group showed diffuse hemorrhage, necrosis and severe edema in focal areas of pancreas. There was obvious adipo-saponification in abdominal cavity. Characteristics such as pancreatic hemorrhage, necrosis, severe edema and adipo-saponification were found in pioglitazone group, but the levels of those injuries were lower in pioglitazone group than those in SAP group. The wet/dry pancreatic weight ratio, ascetic capacity, serum and ascitic activities of anylase in the SAP group were significantly higher than those in the sham group and pioglitazone group respectively （6969.50 ± 1368.99 vs 2104.67 ± 377.16, 3.99 ± 1.22 vs 2.48 ± 0.74, P 〈 0.01 or P 〈 0.05）. According to Kusske criteria, the pancreatic histologic score showed that interstitial edema, inflammatory infiltration, parenchyma necrosis and parenchyma hommorrhage in SAP group significantly differed from those in the sham group and pioglitazone group （7.17 ± 1.83 vs 0.50 ± 0.55, 7.67 ± 0.82 vs 6.83 ± 0.75, P 〈 0.01, P 〈 0.05. The expression of NF-κB and ICAM-1 in sham group was lower than that in SAP group and pioglitazone group （0.50 ± 0.55 vs 33 ± 1.21, P 〈 0.01）. There was a significant difference in the expression of NF-κB and ICAM-1 between SAP group and pioglitazone group （7.50 ±1.05 vs 11.33 ± 1.75, 0.80 ± 0.53 vs 1.36 ± 0.54, P 〈 0.01 or P 〈 0.05） at 12 h after the induction of pancreatitis. CONCLUSION： Pioglitazone attenuates the severity of SAP. The beneficial effect of pioglitazone is multifactorial due to its anti-inflammatory activities, most likely through the inhibition of ICAM-1 expression and NF-κB activation. Specific ligands of PPARy may represent the novel and effective means of clinical therapy for SAP.

Danqi Tablet(丹七片)Regulates Energy Metabolism in Ischemic Heart Rat Model through AMPK/SIRT1-PGC-1α Pathway

Objective To investigate the cardioprotective effect of Danqi Tablet(DQT,丹七片)on ischemic heart model rats and the regulative effect on energy metabolism through peroxisome proliferator-activated receptor-γcoactivator-1α(PGC-1α).Methods Rat ischemic heart model was induced by ligation of left anterior descending coronary artery.Totally 40 Sprague-Dawley rats were randomly divided into sham group,model group,DQT group(1.5 mg/kg daily)and trimetazidine(TMZ)group(6.3 mg/kg daily)according to a random number table,10 rats in each group.Twenty-eight days after continuous administration,cardiac function was assessed by echocardiography and the structures of myocardial cells were observed by hematoxylin-eosin staining.The level of adenosine triphosphate(ATP)in myocardial cells was measured by ATP assay kit.Expressions level of key transcriptional regulators,including PGC-1α,Sirtuin 1(SIRT1),AMP-activated protein kinase(AMPK),and downstream targets of PGC-1α,such as mitofusin 1(MFN1),mitofusin 2(MFN2)and superoxide dismutase 2(SOD2)were measured by Western blot.Expression level of PGC-1αwas examined by immunohistochemical staining.Results The rat ischemic heart model was successfully induced and the heart function in model group was compromised.Compared with the model group,DQT exerted cardioprotective effects,up-regulated the ATP production in myocardial cells and inhibited the infiltration of inflammatory cells in the margin area of infarction of the myocardial tissues(P<0.01).The expressions of PGC-1α,SIRT1 and AMPK were increased in the DQT group(all P<0.05).Furthermore,the downstream targets,including MFN1,MFN2 and SOD2 were up-regulated(P<0.05 or P<0.01).Compared with the TMZ group,the expression levels of PGC-1α,MFN1 and SOD2 were increased by DQT treatment(P<0.05 or P<0.01).Conclusion DQT regulated energy metabolism in rats with ischemic heart model through AMPK/SIRT1-PGC-1αpathway.PGC-1αmight serve as a promising target in the treatment of ischemic heart disease.

Effect of electroacupuncture on the expression of PGC-1α and UCP-1 in the brown adipose tissue of obese rats

Objective： To explore the effect of peroxisome proliferators-activated receptor γ coactivator-1α（PGC-1α） and uncoupling protein-1（UCP-1） in the brown adipose tissue（BAT） of obese rats in the process of acupuncture treatment for obesity.Methods： Fifty clean-grade male Wistar rats with the age of 3 months were randomly divided into highfat diet group（n = 40） and normal diet group（control group, n = 10）. Nutritional obesity animal models were established through feeding with high-fat diet. Twenty-four animal models in the high-fat diet group were established successfully, and then they were randomly divided into model group, acupuncture group and non-acupoint group,with 8 rats in each group. In acupuncture group, Zusanli（足三里ST36） and Tianshu（天枢ST 25） were selected. In non-acupoint group,the non-acupoints located on 5 mm beside ST 36 and ST 25 were selected as acupuncture points, and electroacupuncture intervention was adopted for 5 times/week for 8 weeks. The body mass of obese rats was measured, the body fat ratio in BAT of rats was calculated, and the expression levels of PGC-1α and UCP-1 in BAT of rats were detected by immunohistochemical method.Results： ① After treatment, the body mass of rats in acupuncture group reduced significantly, which increased in the other three groups. The changing value of body mass of rats in acupuncture group was higher than that in model group（P 0.05）, the changing value of body mass of rats in acupuncture group was higher than that in non-acupoint group（P 0.05） and the difference in body mass changing value of rats between non-acupoint group and model group was not statistically significant（P 0.05）,the body fat ratio in BAT of rats in non-acupoint group was lower than that in acupuncture group, and the differences were statistically significant（P0.05）. ② Compared with model group, the body fat ratio in BAT of rats in acupuncture group increased significantly（P 0.05）,and the difference in body fat ratio in BAT of rats between non-acupoint group and model group was not statistically significant（P 0.05）.③ Compared with model group, the PGC-la and UCP-1 levels in BAT of obese rats in acupuncture group increased（P 0.05）, and the difference in expression levels of PGC-la and UCP-1 in BAT of rats between non-acupoint group and model group was not statistically significant（P 0.05）, the expression levels in non-acupoint group were lower than that in acupuncture group, and the differences were statistically significant（P 0.05）.Conclusion： Electroacupuncture at ＂ST 36＂ and ＂ST 25＂ can effectively up-regulate the expression levels of PGC-la and UCP-1 of diet induced obesity rats, it indicates that ＂ST 36＂ and ＂ST 25＂ have close relationship with obesity and it is may be one of the effect mechanisms of electroacupuncture in losing weight through facilitating the ＂browning reaction＂ of white adipose tissue.

Sirtuins Function as the Modulators in Aging-related Diseases in Common or Respectively

INTRODUCTIONAccording to the demographics, the world population over 60 years will double from 605 million to 2 billion people between 2000 and 2050. Aging is a complex process in which the organism and its ability to respond to external stresses become progressive decline.