肾小管上皮细胞损伤促进了对草酸钙晶体的粘附，增加成石风险；而对损伤细胞进行修复或对细胞进行保护可以抑制晶体粘附。细胞对晶体适度内吞减少了细胞表面成石位点，抑制结石形成；而过量内吞则对细胞产生毒性。能否通过控制内吞量从而最大程度地降低成石风险未见报道。本项目通过降解、羧基化和硫酸化对3种防石中草药(广金钱草、泽泻和茯苓)和3种海藻(海带、龙须菜和裙带菜)多糖进行修饰，得到约48种具有不同酸性基团(-OSO3-、-COO-)、不同电荷密度(酸性基团含量约5%、15%和30%)和不同分子量(约3k、10k和30kDa)的衍生多糖。研究这些多糖对草酸钙晶体粘附和内吞的调控机制及其与多糖的构效关系，寻找具有最佳防石效果多糖的结构。从氢键、静电作用、空间匹配和弱相互作用力等方面阐述细胞修复和细胞保护防治肾结石的分子机制，为抑制肾结石形成和开发原创性防石多糖提供启示。该内容未见报道，具有创造性和先进性。

Kidney stone formation is closely related to crystal adhesion and endocytosis. Renal tubular epithelial cell damage promotes cell adhesion to calcium oxalate crystals and increases the risk of stone formation. Repairing damaged cells or protecting cells can reduce crystal adhesion. Moderate endocytosis of cells to crystals can reduce the sites of stone formation on cell surface and inhibit stone formation; however, excessive endocytosis can cause toxicity to cells. Whether it is possible to precisely control the endocytosis so as to minimize the risk of stone formation has not been reported. This project modified three kinds of anti-stone Chinese herbal medicines (desmodium styracifolium, alisma orientale and poria cocos) and three kinds of seaweed (laminaria japonica, gracilaria lemaneiformis and undaria pinnatifida) polysaccharides by degradation, carboxylation and sulfation, and obtained about 48 types of derived polysaccharides with different acidic groups (-OSO3-, -COO-), different charge densities (acidic content of about 5%, 15% and 30%) and different molecular weights (about 3k, 10k and 30kDa). The regulation mechanisms of these polysaccharides on adhesion and endocytosis of calcium oxalate crystals and their structure-activity relationships with polysaccharides were mainly studied so as to find the structure of polysaccharide with the best anti-stone effect. The molecular mechanism of cell repair and cell protection for the prevention and treatment of kidney stones will be illustrated from the aspects of hydrogen bonding, electrostatic interaction, spatial matching, and weak interaction force and so on. It will provide inspiration to suppress the formation of kidney stones and to develop original anti-stone polysaccharides. It has not been reported at home and abroad, which is creative and advanced.