Influence of training in the dark or light phase on physiologic and metabolic parameters ofWistarrats submitted to aerobic exercise

Impact Analysis of Photoperiodic Disorder on the Eyestalk of Chinese Mitten Crab (Eriocheir sinensis) through High-Throughput Sequencing Technology

Light is an indispensable factor in the healthy growth of living organisms, and alterations in the photoperiod can have consequences for body homeostasis. The eyestalk is a photosensitive organ that secretes various hormones to regulate the Chinese mitten crab (Eriocheir sinensis). However, the photoperiod-dependent eyestalk patterns of gene expression that may underlie changes in body homeostasis are unknown. In this study, we investigated the molecular mechanisms involved in eyestalk transcriptomic responses in E. sinensis under different photoperiod regimes on days 2, 4, and 6. The photoperiods tested were 12, 24, and 0 h light/day. In total, we obtained 110, 958, 348 clean datasets and detected 1809 differentially expressed genes (DEGs). Genes involved in the crustacean hyperglycemic hormone superfamily and juvenile hormones were observed, which play important roles in gonadal development, growth, and immunity in E. sinensis and may also be involved in photoperiod adaptation. In addition, the MAPK signaling pathway was the only signaling pathway identified in the continuous light group but was absent in the continuous darkness group. We suggest that the MAPK pathway is highly responsive to light input during the subjective night and insensitive to light during the middle of the subjective day. These results provide insight into the molecular mechanisms underlying the effects of photoperiod on the immune regulation of E. sinensis.

Circadian rhythms modulate the effect of eccentric exercise on rat soleus muscles

We investigated whether time-of-day dependent changes in the rat soleus (SOL) muscle size, after eccentric exercises, operate via the mechanistic target of rapamycin (mTOR) signaling pathway. For our first experiment, we assigned 9-week-old male Wistar rats randomly into four groups: light phase (zeitgeber time; ZT6) non-trained control, dark phase (ZT18) non-trained control, light phase-trained, and dark phase-trained. Trained animals performed 90 min of downhill running once every 3 d for 8 weeks. The second experiment involved dividing 9-week-old male Wistar rats to control and exercise groups. The latter were subjected to 15 min of downhill running at ZT6 and ZT18. The absolute (+12.8%) and relative (+9.4%) SOL muscle weights were higher in the light phase-trained group. p70S6K phosphorylation ratio was 42.6% higher in the SOL muscle of rats that had exercised only in light (non-trained ZT6). Collectively, the degree of muscle hypertrophy in SOL is time-of-day dependent, perhaps via the mTOR/p70S6K signaling.