Methylthiouracil is also utilized in animal models to study cardiovascular and cerebrovascular diseases. Specifically, MTU treatment significantly reduces the peritoneal leakage of dye triggered by LPS. Given that the average circulating blood volume in mice is 72 mL/kg and the average weight of the mice used in this study is 27 g, with an estimated blood volume of 2 mL, the administration of MTU at doses of 142 or 284 μg/kg achieves a maximum concentration of 10 or 20 μM in the peripheral blood^[1].

Human Umbilical Vein Endothelial Cells (HUVECs) are exposed to various concentrations of Methylthiouracil (MTU), ranging from 0 to 20 μM, for six hours following an initial treatment with LPS (100 ng/mL) for four hours. MTU effectively reduces LPS-induced hyperpermeability in these endothelial cells, showing maximal efficacy at concentrations exceeding 5 μM. Additionally, subsequent treatment with MTU at 10 or 20 μM suppresses the formation of LPS-induced paracellular gaps while promoting the development of dense F-actin rings. To evaluate MTU's safety, cellular viability assays are conducted on HUVECs treated with MTU for 24 hours, confirming that MTU up to 20 μM does not compromise cell viability^[1].