ABSTRACT
Objective To observe the changes of bone formation in type 2 diabetes mellitus (T2DM) mice and the effect of different exercises on their cAMP/CREB/Atf4 pathway and bone formation.Methods Forty four-week-old C57BL/6 male mice were randomly divided into a normal control group (ZC) of 10 and a T2DM group of 30.T2DM was induced using the high-fat diet and injection of streptozotocin.Then,the T2DM mice were randomly divided into a T2DM control group (TC),a T2DM swimming group (TS) and a T2DM downhill running group (TD),each of 10.The TS and TD groups were trained for eight weeks as their group names indicated.Then the concentration of cAMP in serum was tested using the enzyme-linked immunosorbent assay (ELISA).The reverse transcription-polymerase chain reaction (RT-PCR) was used to test the mRNA expression of the cAMP-response element binding protein (CREB),activate transcription factor 4 (ATF4),osteocalcin (OC),bone gla-protein (OCN)and bone sialoprotein (BSP) in the left tibia,and Western blotting was employed to test the protein expression of CREB in the right femur.The bone marrow mesenchymal stem cells (BMSCs) were taken and induced to differentiate into osteoblasts (OBs) and dyed using the alkaline phosphatase (ALP) solution.The left side hindlimb bone was taken and scanned the bone mineral density (BMD) of the distal end using the Skyscan Micro-CT.Results Compared with group ZC,the concentration of cAMP declined in group TC.Moreover,the mRNA expression of CREB,ATF4,OC,OCN and BSP as well as the protein expression of CREB of group TC were significantly down-regulated(P＜0.01 or P＜0.05),together with the OB osteogenic capacity and BMD (P＜0.01) compared to group ZC.Compared with group TC,significant increase was observed in the mRNA expression of OC and OCN (P＜0.01 or P＜0.05),as well as the OB osteogenic capacity of group TS.The concentration of cAMP of group TD decreased,the mRNA expression of CREB,ATF4,OC and OCN,as well as the protein expression of CREB were all significantly up-regulated (P＜0.01 or P＜0.05) compared with group TD.The OB osteogenic capacity and BMD(P＜0.05) of group TD also increased significantly.Compared with group TS,the concentration of cAMP(P＜0.05) and the OB osteogenic capacity increased,and the mRNA expression of CREB,ATF4 and OC of group TD increased significantly(P＜0.01 or P＜0.05).Conclusion The bone formation metabolism of type 2 diabetic mice is inhibited.The downhill running is superior to swimming in promoting the osteoblast differentiation and bone formation,as well as the bone mineral density through activating the cAMP/CREB/Atf4 pathway in the bone of T2DM mice.
ABSTRACT
Several studies have reported that molecular hydrogen (H<sub>2</sub>) acts as a therapeutic medical gas owing to scavenging reactive oxygen species (ROS). However, little is known about effects of H<sub>2</sub> on exercise-induced oxidative stress. The purpose of this study was to investigate the effects of weekly hydrogen bathing on exercise-induced oxidative stress and delayed-onset muscle soreness (DOMS). Nine healthy and active young men participated in this study, and each subject performed hydrogen bathing trial and placebo bathing trial in a crossover design. The subjects performed downhill running (8 % decline) at 75 % peak oxygen uptake (VO<sub>2</sub>peak) for 30 min, and each subjects conducted hydrogen or placebo bathing for 20 min, respectively, 1-6 days after downhill running. Before and after exercise, we measured visual analogue scale (VAS) and collected blood samples (Pre- and 5 min, 60 min after the end of bathing, 1day, 2days, 3days, 7days after downhill running). Blood sample analyses include creatine kinase (CK), myoglobin (Mb), malondialdehyde (MDA), reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), myeloperoxidase (MPO), interleukin-6 (IL-6), interleukin-17a (IL-17a) and lactate concentrations. Weekly hydrogen bathing had no effects of exercise-induced oxidative stress and muscle damage. On the other hand, hydrogen bathing significantly reduced DOMS (VAS) 1 and 2days after downhill running (p=0.033). These findings suggest that hydrogen bath after downhill exercise can be effective for reduction of DOMS.
ABSTRACT
The purpose of this study was to investigate the usage of the lower limb muscles (quadriceps femoris : QF, m. vastus lateralis : VL, m. rectus lemons : RF, m. vastus medialis : VM, m. vastus intermidialis : VI, hamstring : HM, m. gastrocnemius : UN, tihialis anterior : TA) and blood lactic acid concentration during uphill ( : UR +5 %) and downhill running ( : DR - 5 %) . We used magnetic resonance imaging (MRI) as one of the major indices. Seven healthy male volunteers participated in this study. T 2-weighted MR imaging, muscle surface temperature and blood lactic acid concentration were measured before and after UR and DR. In MRI imaging, the T2 value was defined as the area in which a high signal appeared after exercise.<BR>The value of the blood lactic acid concentration of UR was higher than that of DR (p<0.001) . After DR, the muscle surface temperature of RF was lower in comparison with other muscles (p< 0.05) . After UR, the T2 value of RF (p<0.05), HM (p<0.01) and UN (p<0.05) was higher than after DR exercise. During UR, a positive correlation (r=0.818) existed between the T 2 value of GN and blood lactic acid concentration (P<0.05) . During DR, a positive correlation (r=0.739) was also observed between the T 2 value of QF and blood lactic acid concentration (p<0.05) .<BR>From these results, we conclude that (1) the pattern of usage of lower limb muscles differs during UR and DR, (2) the most mobilized muscles in the lower limbs for UR are GN and HM, and (3) the most mobilized muscle in the lower limbs for DR is QF, respectively. These findings show that different exercises affect the blood lactic acid concentration differently.