Modulation of Rat Kidney Stone Crystallization and the Relative Oxidative Stress Pathway by Green Tea Polyphenol

The role of tea polyphenol (TP) in modulating kidney stone crystallization and regulating the relative nephropathy pathway of rats was investigated. Calcium oxalate (CaOx) crystallization and oxidative stress are essential for kidney stone diseases. The kidney stone model in a rat was established by using ethylene glycol to affect the oxalic acid metabolism. The crystallization process of CaOx in the rat kidney was modulated by different TP intakes. At the same time, the effects of different types of CaOx, extracted from the rat kidney, on the proliferation and differentiation of HK-2 cells were also studied. The results showed that calcium oxalate monohydrate crystals were obtained in the blank control and the low-dose TP groups. However, CaOx crystals extracted from higher-TP-intake groups were mainly calcium oxalate dihydrate. Moreover, the size of the CaOx crystals produced in TP intake groups was much smaller than that of the blank control group. Cell experiment results show that TP can effectively reduce the damage of CaOx crystals to HK-2 cells. Further research found that TP can significantly improve oxidative stress in cases of kidney stones. TP has been proven to control CaOx crystallization in vitro, but the in vivo research results obtained through the rat stone model in this paper are novel and originally important for researching the relationship between tea drinking and preventive treatment of kidney stone diseases.