Abstract: Objective To explore the effect of tolvaptan on aquaporin 2 and cell apoptosis in inner medullary collecting duct cells, to research the influence of tolvaptan on renal tubular function. Methods The cells were treatment with different concentrations of tolvaptan, then the expression of aquaporin 2 was detected by Western blot, the caspase 3 activity was tested by the kit, the cell apoptosis was determined by MTS and flow cytometry; the model mice were treatment with different concentrations of tolvaptan, the β2-MG and NAG were tested by the kit. Results Tolvaptan significantly decreased the protein expression of aquaporin 2（p<0.05）, and had no effect on the caspase 3 activity and cell apoptosis. Tolvaptan had no effect on the concentration of the β2-MG and NAG. Conclusions Tolvaptan decreases meaningfully the protein expression of aquaporin 2 and has no effect on apoptosis and renal tubular function.

Key words: Keyword: Tolvaptan , aquaporin 2, β2-MG, AVP, apoptosis