Abstract: 【Abstract】Objective To establish a model of rats with high indoxyl sulfate (IS) level and then to study the effect of different dialysis modalities on clearance of IS. Methods Rat model of high IS level was established in 24 male SD rats. They were then divided into control group (n=6), HD (hemodialysis) 4h group (n=6), HD 6h group (n=6) and HDF (hemodiafiltration) group (n= 6). Arterial blood sample was taken every 30 minutes during dialysis. Blood IS concentration was assayed by HPLC. SPSS 24.0 was used for statistical analyses; P<0.05 was considered to be significant. Results ①Establishment of the rat model: IS level decreased significantly [(57.79±16.12)μg/ml vs. (49.26±10.80)μg/ml] after model establishment for 30～60min, then maintained the level (46.48±8.00)μg/ml to 360 min (P=0.178, F=4.858). ②IS level decreased gradually with HD (F=24.719, P＜0.001 for HD group; F=44.086，P＜0.001 for HDF group; F=52.481, P＜0.001 for HD 6h group). The clearance of IS with HDF was significantly higher than that with HD (F=7.567, P=0.020). IS level did not change significantly when HD prolonged from 240 min to 360 min (P= 0.555, 95% CI: -0.777～1.284). Conclusion The rat model of renal insufficiency with significant increase of IS level and the rat model treated with HD or HDF were successfully established. The clearance rate of IS using HDF was significantly higher than that using HD. The clearance ability of HD reached saturation about 4 hours after the treatment, and the clearance ability could not be further increased beyond 4 hours.

Key words: Hemodialysis, Hemodiafiltration, Indoxyl sulfate