Résumé
Objective@#To investigate the effect of brain and muscle arant-like-1 (Bmal1) and miRNA-155-5p on the proliferation ability and aging of bone marrow mesenchymal stem cells (BMMSCs) to provide an experimental basis for elucidating the mechanism of bone senescence.@*Methods @# BMMSCs were extracted from the femur medullary cavity of 1-month-old mice, purified and cultured via the whole bone marrow mesenchymal adherent method and passed to P3. The characteristics of BMMSCs were detected by flow cytometry. BMMSCs were transfected with lentivirus to construct stable miR-155-5p and Bmal1 overexpression/interference BMMSCs. shRNA-transfected BMMSCs were identified by qRT-PCR. The proliferation activities of miR-155-5p and Bmal1 overexpression/interference BMMSCs were detected via CCK-8 assay. The apoptosis rates were measured by flow cytometry. The aging status of BMMSCs was identified with the senescence-associated β-galactosidase (SA-β-Gal) test. The expression of senescence-related genes P16 and P53 was detected by qRT-PCR.@*Results@#The shRNA-transfected BMMSCs were successfully generated. The proliferation ability decreased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 increased when miRNA-155-5p was overexpressed. The proliferation ability increased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 decreased when miRNA-155-5p was inhibited. The effect of Bmal1 is opposite to that of miRNA-155-5p.@*Conclusions @# The expression of Bmal1 promotes the proliferation and antiaging ability of BMMSCs, while miRNA-155-5p inhibits the proliferation and accelerates the aging of BMMSCs.
Résumé
Objective To investigate the effect of 36 h continuous sleep deprivation(SD) on circadian clock gene expression in the rat liver and kidney and the alteration of urine biomarker levels.Methods Twelve rats were randomly divided into control group and SD group.An SD device was used to deprive the rats of sleep.After 36 h continuous SD, the abdominal cavity was exposed to obtain livers and kidneys, and RT-PCR and Western blotting were used to detect expression of clock genes.Then,the pelvic cavity was exposed to obtain urine, and the changes in bio-marker total bile acids(TBA) were tested with ELISA.Results Compared with the control group, the mRNA level of liver clock and bmal1 was obviously reduced in the SD-treated rats (P<0.05).However, no obvious change was found in the samples from the kidney.Sharp down-regulation of CLOCK and BMAL1 protein expression was also observed in the rat liver after SD treatment.Urine TBA content in SD treated rats was raised obviously (P<0.001), compared with control.Conclusion Thirty-six hours of continuous SD could result in deregulation of circadian clock gene and cholesterol metabolism disorder in the rat liver.TBA might be used as a noninvasive biomarker of liver injury under SD stress conditions.