The Biological Profiles Of Selenosulfate And The Size Effect Of Nano-Se In Vivo

Selenium (Se) is an essential trace element to human. At the nutritional doses, Se can well enhance the activities of selenoenzymes. At the supranutritional doses, Se can increase the accumulation of low molecular weight selenocompounds and the activity of glutathione S- transferase, having the potency in chemoprevention. At the higher doses, especially the maximum tolerated dose (MTD), Se can increase the cure ratio of chemotherapy. Selenosulfate is usually used as a precursor of selenide to synthesis various kinds of material. Its biological profiles were investigated in present study.Nano-Se is a kind of selenium which has low toxicity. Nano-Se of has size effect on scavenging free radicals, while Nano-Se at nutritional dose does not have size effect on enhancing the selenoenzymes' activities. Se supplementation at supranutritional doses has the potency in chemoprevention; the chemopreventive effect of selenium which has lower toxicity would be more promising. Therefore, size-dependent effect of Nano-Se at the dose beyond nutritional level was explored.The major findings of this study are included in following four aspects:1, at the nutritional dose, selenosulfate has the similar but significantly lower bioavailability as compared with selenite. At the supranutritional doses, it has the same biological functions to selenite. However, at the toxic doses, it has lower short-term toxicity than selenite, but without lowering Se accumulation.2, selenosulfate has dose effect on decreasing the lethal toxicity of Cisplatin, which is correlated with Se accumulations in tissues and with kidney GST activity. Blood Se can be considered as a clinical biomarker for evaluating the host tolerance to Cisplatin.3, selenosulfate can efficiently reduce the nephrotoxicity caused by Cisplatin. Furthermore, selenosulfate did not affect the therapeutic effect of Cisplatin in solid tumor model and could increase the cure ratio of Cisplatin in ascites tumor model of H22 hepatic tumor. 4, Nano-Se at the doses beyond nutritional level can size-dependently increase the Se accumulation and GST activity in mice. The potency of size effect of Nano-Se on the biomarker is correlated with the saturation profile of the tested biomarker.5, the temperature effect on biological functions of Nano-Se is due to the changes of Nano-Se in diameter and in shape.