[Effects of different types of exercise on contractile properties and expressions of MuRF1, PGC-1α /FNDC5 in soleus muscle of unloaded rats].

Objective: To investigate the effects of aerobic versus resistance exercise on soleus muscle contractile properties and the expressions of MuRF1, PGC-1α and FNDC5 in amyotrophic rats after unloading, and the possible molecular biological mechanisms. Methods: Male Wistar rats were randomly divided into recovery group (CT), aerobic exercise group (A), resistance exercise group (R) and control group (C), with 6 rats in each group. The control group did not receive any treatment. The other three groups underwent tail suspension for 2 weeks, and then the recovery group recovered quietly. The aerobic group and the resistance group underwent a 2-week exercise intervention. Exercise plan: the aerobic group rats were treated with treadmill speed corresponding to 65% maximum oxygen uptake (VO2max), 60 min/d, 5 d/w; the rats in the resistance group were allowed to climb the ladder with 65% of the maximum voluntary weight-bearing (MVCC) for 3 times, with a total of 5 sets. Each time had a rest of 1 min, with an interval of 2 min among sets, and 5 d/w. Fasting for 24 hours after the last exercise, the soleus muscle samples were collected to observe the histological changes, test the contractility, and detect MuRF1 and PGC-1α and FNDC5 expressions. Results: compared with the control group, the body weight, soleus muscle wet weight, average cross-sectional area of muscle fibers and muscle contractility of the recovery group were decreased significantly(P<0.01), and the expression of MuRF1 was increased significantly(P<0.01). Compared with the recovery group, the body weight, wet weight of soleus muscle, the average cross-sectional area of muscle fiber and muscle contractility of rats in aerobic group and resistance group were increased (P<0.01), the expression of PGC-1α/FNDC5 was increased (P<0.01) and the expression of MuRF1 was decreased significantly (P<0.01). Compared with the aerobic group, the expression of PGC-1α in soleus muscle of rats in the resistance group was increased (P<0.05), while the expression of MuRF1 was decreased (P<0.05). Conclusion: Aerobic and resistance exercise can significantly improve muscle contractility, upregulate the expression of PGC-1α/FNDC5, and inhibit the expression of MuRF1, indicating that the molecular mechanisms of aerobic and resistance exercise to improve unloaded muscular atrophy may be related to PGC-1α and MuRF1.

[Effects of heavy-load exercise on skeletal muscle cells apoptosis and mechanisms of mitochondrial apoptosis in rats].

OBJECTIVE: To analyze the molecular mechanisms of skeletal muscle cells apoptosis induced by heavy-load exercise with Omi as the entry point. METHODS: One hundred and twenty-six adult SD rats were randomly divided into five groups: control group(C), eccentric exercise group (E), simple blocking group (U), DMSO group (D) and exercise block group (EU). In addition to the C group, the other four groups were randomly divided into 0 h after experiment, 12 h after experiment, 24 h after experiment, 48 h after experiment and 72 h after experiment with 6 rats in each group. E and EU group were submitted to a heavy-load exercise on a treadmill down a 16° decline, 16 m/min for 90 minutes. U, D and EU group were one-time intervened with drugs. U and EU groups were intraperitoneally injected with 1.5 µmol/kg ucf-101, D group were intraperitoneally injected with 1.5 µmoL/kg 0.5% DMSO. The rats were sacrificed in batches at different time points after experiment, then the soleus were saved to detect the Caspase-3,-8,-9,-12 activities and protein expressions of Omi and XIAP. RESULTS: Compared with group C, the mitochondrial distribution and morphology appeared the typical ultrastructure pathological changes, the opening degree of MPTP was increased significantly (P＜0.01) or (P＜0.05), protein expressions of Omi and XIAP were increased significantly (P＜0.01 or P＜0.05), the activities of Caspase-9 and Caspase-3 were increased significantly (P＜0.01 or P＜0.05) in group E. Compared with group C, there was no significant difference in XIAP protein and caspase-9, - 3 activities in group U and Group D. The change trend of XIAP protein and Caspase-9, - 3 activities was the same as those between EU group and E group, but the change range of XIAP protein in EU group was significantly higher than that in E group (P＜0.01), and the change ranges of caspase-9, - 3 activities in EU group were significantly lower than those in E group (P＜0.01). CONCLUSION: A single heavy-load exercise can induce changes in the mitochondria morphology and structure in rats, open the high permeability of MPTP, and improve the expression of Omi protein, then through its downstream XIAP-Caspase pathway, start the mitochondrial apoptosis pathway mediated by caspase-9, and finally lead to myocyte apoptosis. The inhibition of Omi can reduce the cell apoptosis level of motor induced skeletal muscle cells.

The nymph, habitat, and status of Eatonigenia in China (Ephemeroptera: Ephemeridae).

The nymphs of a new species of Eatonigenia have more modified labrum and smaller foreclaws than congeners, and the males have a more reddish-brown colored body, cerci, genitalia and more sclerotized projections of gonopores. These characters indicate a new species which is named E. zhangi sp. nov. The nymphs live in fine sandy/muddy substrates of large rivers.

The complete mitochondrial genome of Paegniodes cupulatus (Ephemeroptera: Heptageniidae).

The complete mitochondrial genome of Paegniodes cupulatus (Ephemeroptera: Heptageniidae), which is sequenced for the first time here, is 15,715 bp in length, containing 13 protein-coding genes, 2 rRNAs, 22 tRNAs and a control region. The overall base composition of the genome is 33.1% for T, 20.7% for C, 32.5% for A and 13.7% for G, with an AT bias of 65.6%.