Effect of 1a,25(OH)2 D3 on circadian clock gene expression in cardiac myocytes / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the effect of 1a,25(OH)2 D3 on circadian clock gene expressions in cardiac myocytes.Methods Cultured cardiac myocytes isolated from 7 -day -old Sprague -Dawley(SD)rats were identified by immunofluorescence.The medium including 1a,25 (OH)2 D3 (final concentrations were 0 nmol/L,1 nmol/L, 10 nmol/L,50 nmol/L and 100 nmol/L)were added to primary myocardial cells to culture for 2 h and then total RNA was extracted.Real -time polymerase chain reaction (RT -PCR)was applied to analyze myocardial cells circadian clock gene (Bmal1,Per2,Rev -erba)transcript levels to determine optimum concentration of 1a,25(OH)2 D3 .Then, the primary myocardial cells cultured for 72 h were divided into 3 groupsthe control group was of serum -free culture medium;serum shock group was of DMEMcontaining 50%volume fraction of horse serum cultured 2 h;1a,25(OH)2 D3 treatment group receiving 1a,25 (OH)2 D3 at optimal concentration cultured 2 h.The cells were collected at 7 time points (0 h,4 h,8 h,12 h,16 h,20 h,24 h)and then total RNA was extracted.RT -PCR was applied to analyze circa-dian clock gene (Bmal1,Per2,Rev -erba)transcript levels in the myocardial cells.Results In the presence of 50 nmol/L 1 a,25(OH)2 D3 ,the Bmal1 mRNA expression showed the highest level,but the Per2 and Rev -erba mRNA expression levels were minimum.Compared with the control group,both 1a,25 (OH)2 D3 treatment group and serum shock group caused day -cycle rhythmic oscillation in circadian clock genes(Bmal1,Per2,Rev -erba)in the cardiac myocytes.And the expressions pattern of Bmal1 and Per2 genes were in the opposite phase.While Bmal1 gene expres-sion appeared at peak at 12 h,Per2 gene expression appeared in a trough.Expression of Rev -erba gene trend began to rise at 8 h,and the highest expression level appeared at 12 -16 h.Conclusions 1a,25(OH)2 D3 can affect Bmal1, Per2 and Rev -erba mRNA expressions of circadian clock genes in the cardiac myocytes.