Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
Physiol Res. 2021 Dec 30;70(6):913-920. doi: 10.33549/physiolres.934766. Epub 2021 Oct 30.
Extracellular DNA (ecDNA) activates immune cells and is involved in the pathogenesis of diseases associated with inflammation such as sepsis, rheumatoid arthritis or metabolic syndrome. DNA can be cleaved by deoxyribonucleases (DNases), some of which are secreted out of cells. The aim of this experiment was to describe plasma DNase activity in relation to extracellular DNA in adult rats, to analyse potential sex differences and to prove whether they are related to endogenous testosterone. Adult Lewis rats (n=28) of both sexes were included in the experiment. Male rats were gonadectomized or sham-operated and compared to intact female rats. Plasma ecDNA and DNase activity were measured using fluorometry and single radial enzyme diffusion assay, respectively. Concentrations of nuclear ecDNA and mitochondrial ecDNA were determined using real-time PCR. Females had 60% higher plasma DNase activity than males ( p=0.03). Gonadectomy did not affect plasma DNase in males. Neither the concentration of total ecDNA, nor nuclear or mitochondrial DNA in plasma differed between the groups. No significant correlations between DNase and ecDNA were found. From previous studies on mice, it was expected, that male rats will have higher DNase activity. In contrast, our study in rats showed the opposite sex difference. This sex difference seems not to be caused by endogenous testosterone. Interestingly, no sex differences were observed in plasma ecDNA suggesting a complex or missing association between plasma ecDNA and DNase. The observed sex difference in plasma DNase should be taken into account in animal models of ecDNA-associated diseases.
细胞外 DNA（ecDNA）激活免疫细胞，并与炎症相关疾病的发病机制有关，如败血症、类风湿关节炎或代谢综合征。DNA 可被脱氧核糖核酸酶（DNases）切割，其中一些酶从细胞中分泌出来。本实验旨在描述成年大鼠血浆中与细胞外 DNA 相关的 DNase 活性，分析潜在的性别差异，并证明其是否与内源性睾酮有关。本实验纳入了成年 Lewis 大鼠（n=28），包括雄性和雌性大鼠。雄性大鼠接受去势或假手术，并与完整的雌性大鼠进行比较。使用荧光法和单径向酶扩散测定法分别测量血浆 ecDNA 和 DNase 活性。使用实时 PCR 测定核 ecDNA 和线粒体 ecDNA 的浓度。女性的血浆 DNase 活性比男性高 60%（p=0.03）。去势对雄性大鼠的血浆 DNase 没有影响。各组血浆总 ecDNA 浓度、核 ecDNA 或线粒体 DNA 均无差异。未发现 DNase 与 ecDNA 之间存在显著相关性。从先前对小鼠的研究中可以预期，雄性大鼠将具有更高的 DNase 活性。相反，我们在大鼠中的研究显示出相反的性别差异。这种性别差异似乎不是由内源性睾酮引起的。有趣的是，血浆 ecDNA 中未观察到性别差异，这表明血浆 ecDNA 和 DNase 之间存在复杂或缺失的关联。在与 ecDNA 相关疾病的动物模型中，应考虑到血浆中观察到的 DNase 性别差异。
