The circadian clock has been linked to female reproductive physiology and endocrine in mammals. Epidemiological studies of female shift workers have shown increased rates of abnormal reproduction and adverse pregnancy. But little is known how the circadian rhythms affect reproduction. The aim of the present study was to investigate the influences of circadian rhythms on estrous cycle in female mice using clock gene Rev-erb-α knock out (Rev-erb-α(-/-)) mice. To test the fertility of Rev-erb-α(-/-) mice, litter sizes were counted after mating with C57BL/6J male mice. HE staining was used to observe the change of follicle development. The number of embryos of Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice was compared 1.5 d after mating with C57BL/6J male mice. Then Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice were housed to adult, and daily vaginal lavage with 0.9% saline was used to monitor estrous cycle for at least 30 days. Quantity of various cells was counted on specified smears views after staining. We observed estrous cycles of Rev-erb-α(+/+) and Rev-erb-α(-/-) female mice using line plots and periodic spectrograms. The results showed that the Rev-erb-α(-/-) female mice were infertility, and the number of embryos of Rev-erb-α(-/-) females was less than that of Rev-erb-α(+/+) females. However, the follicle development of Rev-erb-α(-/-) female mice was normal. The estrous cycle of Rev-erb-α(-/-) female mice was 3.22 days longer than that of Rev-erb-α(+/+) female mice. The results suggest that loss of Rev-erb-α prolongs estrous cycle, which is probably one of the reasons for female mice infertility, and circadian rhythm is important for mammalian estrous cycle.
Animals ; Circadian Rhythm ; Estrous Cycle ; Female ; Fertility ; Litter Size ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Nuclear Receptor Subfamily 1, Group D, Member 1 ; genetics ; physiology ; Pregnancy

OBJECTIVETo investigate the changes in the expression of nuclear receptor subfamily1 (Nr1d1) in the lungs of rats with ventilation-induced lung injury and explore the molecular mechanism.

METHODSSeventy-two rats were randomly divided into 4 groups for observation at 4 time points (1:00 AM, 7:00 AM, 1:00 PM and 7:00 PM), and each group was further divided into 3 subgroups (Group FB, Group LV and Group HV). After ventilation for 3 h, the rats were sacrificed and lung tissue samples were obtained for testing the expression of Nr1d1 using gene chip technology and RT-PCR.

RESULTSNr1d1 gene expression was down-regulated in HV group as shown by gene chip RT-PCR data. Cosine analysis showed that Nr1d1 expression exhibited a rhythmicity in FB group (P<0.05).

CONCLUSIONThe rhythmicity of Nr1d1 expression disappears as the tidal volume the increase. Diminished Nr1d1 expression is closely correlated with ventilation-induced lung injury in rats.

Animals ; Circadian Rhythm ; Down-Regulation ; Female ; Lung ; metabolism ; Male ; Nuclear Receptor Subfamily 1, Group D, Member 1 ; metabolism ; Oligonucleotide Array Sequence Analysis ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Respiration, Artificial ; adverse effects ; methods ; Reverse Transcriptase Polymerase Chain Reaction ; Tidal Volume ; Ventilator-Induced Lung Injury ; metabolism