Objective: To observe effect of Fuzi Lizhong decoction on aquaporin 4(AQP4) in rats with spleen Yang deficiency syndrome and discuss its antidiarrheal mechanism. Method: One hundred Wistar rats were randomly divided into control group

model group

low-dose group

middle-dose group and high-dose group

20 rats each group. low-dose group

middle-dose group and high-dose group were ig given with Fuzi Lizhong decoction according to 10

20

40 g·kg-1 based on model group

once a day for four weeks.colon was collected as sample to examine content of AQP4 by ELISA method and expression of AQP4 mRNA by RT-PCR method. Result: Compared with control group

in model group both content of AQP4(13.25±4.22) ng·L-1 and expression of AQP4 mRNA (0.38±0.11)reduced (P<0.01 or P<0.05). Compared with model group

in middle-dose group both content of AQP4 (23.84±5.68)ng·L-1and expression of AQP4 mRNA (0.54±0.26)increased (P<0.05). Compared with model group

in high-dose group both content of AQP4 (28.98±6.12)ng·L-1and expression of AQP4 mRNA (0.62±0.32)increased significantly (P<0.01). Conclusion: Fuzi Lizhong decoction could recover content of AQP4 and expression of AQP4 mRNA

and high dose had a better effect. Fuzi Lizhong decoction could up-regulate expression of AQP4 mRNA and promote gastrointestinal reabsorption of water

which perhaps are one of its antidiarrheal mechanisms.