Effect of estrogen on expression of cysteine-rich secretory protein CRISPLD2 in myocardium of mice with sepsis

Abstract

To investigate the effect of estrogen on expression of the cysteine-rich secretory protein containing LCCL domain 2 (CRISPLD2) in myocardium of lipopolysaccharide (LPS)-induced mice model of sepsis. Totally 12 female and 12 male Balb/c mice of specific pathogen-free (SPF) level with 7 weeks were served as objectives. The female and male mice were randomly divided into model groups and control groups, respectively, with 6 mice in each group. The model of sepsis was reproduced by intraperitoneal injection of 10% LPS (5 mg/kg), and the mice in control groups were injected with the same volume of normal saline. The general condition of mice during experiment was observed at 24 hours after injection. All the mice were sacrificed and the heart was harvested after collecting the whole blood. The concentration of estrogen in serum was determined by double antibody sandwich enzyme linked immunosorbent assay (ELISA). The myocardial tissue homogenate was prepared at the same time, and the total protein was extracted. The expression level of CRISPLD2 was determined by Western Blot. Pearson correlation analysis was used to analyze the bivariate correlation. All of the experimental mice survived at 24 hours after injection. The mice in the model groups showed disorder and gray signs of body hair, with diarrhea and decreased appetite. No significant abnormality was observed in the control groups. There was no significant difference in the body weight or concentration of estrogen in serum between model and control group of both female and male mice [body weight (g): 24.6±1.8 vs. 24.5±1.3 in male mice, 18.0±0.8 vs. 17.5±1.1 in female mice; estrogen (ng/L): 11.93±2.59 vs. 12.17±3.87 in male mice, 28.20±5.75 vs. 29.82±6.10 in female mice, all P > 0.05]. There was no statistical difference in the expression of CRISPLD2 in myocardium between male control mice and female control mice (gray value: 1.02±0.19 vs. 1.00±0.11, P > 0.05). No significant difference in the expression of CRISPLD2 in myocardium was found between female sepsis mice and female control mice (gray value: 1.05±0.13 vs. 1.00±0.11, P > 0.05). The expression of CRISPLD2 in myocardium of male sepsis mice was significantly lower than that of male control mice (gray value: 0.29±0.08 vs. 1.02±0.19, P < 0.01), and it was significantly lower than that of female sepsis mice (P < 0.01). It was shown by correlation analysis that the expression level of CRISPLD2 in myocardium of sepsis mice was significantly correlated with serum estrogen concentration [R2 = 0.736, 95% confidence interval (95%CI) = 0.560-0.960, P < 0.001]. In female mice with sepsis, the expression of CRISPLD2 is comparable to that of female healthy mice. It is suggested that estrogen can maintain the expression of CRISPLD2 in LPS-induced septic mice at the normal level.