Abstract:

[Abstract] Objective To explore the effect of modified Zexie Decoction on renal aquaporin-2 (AQP2) expression in high-salt hypertensive rat. Methods Hypertensive rats model was established by feeding rat with 8% high salt. Rats (n= 50) were divided into model group, modern medicine group, traditional Chinese medicine groups of high, medium, low dose, with 10 rats in each group. The other 10 rats were fed with ordinary diet as normal group. Rats in traditional Chinese medi? cine of high, medium, low groups were given Zexie Decoction suspension of 16.2, 10.8 and 5.4 g/(kg· d) respectively; Rats in modern medicine group was given Valsartan hydrochlorothiazide 16.65 mg/(kg· d); the model group and normal group was ad? ministered with equal volume of distilled water. Animals were feed with medications at 1 mL/100 g by gavage for 4 weeks. On the 1 st , 4th , 7th , 14th and, 28th day of administration, we measured SBP and collected 24 h urine. We employed immunohis? tochemistry to detect renal AQP-2 protein expression level and RT - PCR to detect renal AQP -2 mRNA transcription level. Results The rank of SBP from high to low is: model group > traditional Chinese medicine medium and low dose groups > traditional Chinese medicine high dose group and western medicine group > normal group. The rank of urine volume from high to low is: Western medicine group and traditional Chinese medicine high dose group > traditional Chinese medicine me? dium and low dose group > normal group, the difference was not statistically significant between traditional Chinese medi? cine medium and low dose group , or between western medicine group and traditional Chinese medicine high dose group. The renal AQP - 2 in epithelial cells along the collecting duct wall of rats in model group show brown particles which are darker and wider distributed than those in normal group and traditional Chinese medicine of high, medium, low dose groups. RT - PCR results show that AQP-2 mRNA expression is highest in rats of model group and lowest in rats of traditional Chi? nese medicine high dose group (P < 0.05). No statistical significance of AQP mRNA level was found between traditional Chi? nese medicine low group and model group (P < 0.05). Conclusion Modified Zexie Decoction can lower blood pres? sure by inhibiting the expression of AQP-2

Key words: high salt, hypertension, kidney, Aquaporin - 2., SBP, modified zexie decoction