Abstract: Objective: To analyze the dose-effect relationship of dryness effect of Atractylodes Rhizoma based on the expressions of stem cell factor (SCF) and its receptor c-kit mRNA in colon tissue and to ensure the basic dose of Atractylodes Rhizoma which caused the dryness reaction in the mice,and to provide the reference for clinical medicine. Methods: Seventy-five C57BL/6 mice were divided into control group,185, 370, 555, and 740 mg·kg^-1 Atractylodes oil groups, 15 mice in each group, and the administration volume was 0.015 mL·g^-1;the mice were administered intragastrically for 14 d,and the mice in control group were given the same volume of 1% Tween-20 solution. The average daily water intake and daily average urine output of the mice were detected. Immunohistochemical method was used to detect the expression levels of aquaporin-2 (AQP2) in the kidney tissue of the mice;the sleen and kidney coefficients of the mice were calculated, and RT-PCR method was used to determine the expression levels of SCF and c-kit mRNA in the colon tissue; the dryness effects of the mice in various groups were investigated according the obove indicatros. Results: Compared with control group, the average daily water intakes, daily urine outputs,the AQP2 expression levels in kidney tissue,the kidney coefficients and spleen coefficients of the mice in 185 and 370 mg·kg^-1 Atractylodes oil groups had no significant differences (P>0.05); the expression levels of SCF mRNA in colon tissue of the mice were significantly increased (t=4.859, P<0.01; t=6.651, P<0.05); the expression level of c-kit mRNA in colon tissue of the mice in 185 mg·kg^-1 Atractylodes oil group was significantly increased (t=2.946, P<0.05), but in 370 mg·kg^-1 Atractylodes oil group had no statistically significant difference(P<0.05).Compared with control group, the average daily urine output and the expression level of c-kit mRNA in colon tissue of the mice in 555 mg·kg^-1 Atractylodes oil group were significantly reduced (t=7.708, P<0.01; t=8.465, P<0.01), but there were no statistically significant differences in other indicators (P>0.05). Compared with control group, the water intake and the AQP2 protein expression level in kidney tissue of the mice in 740 mg·kg^-1 Atractylodes oil group were significantly increased (t=3.554, P<0.01; t=4.636, P<0.01),and the average daily urine volume, the spleen coefficient,and the expression levels of SCF and c-kit mRNA in colon tissue of the mice were decreased significantly (t=7.708, P<0.01; t=4.985, P<0.01; t=7.314, P<0.01; t=28.45, P<0.01). Conclusion: Low doses (185 and 370 mg·kg^-1) of Atractylodes oil show no obvious dryness effect in the healthy mice, and the high doses(555 mg·kg^-1 and above) of Atractylodes oil may show obvious dryness effect by influencing the SCF/c-kit signal pathway.

Key words: Atractylodes Rhizoma, volatile oil, stem cell factor, stem cell factor receptor, c-kit, dryness effect