Objective: To observe the effects of chemical splitting fractions of Mori Cortex on water sodium retention in rats with Adriamycin-induced nephrotic syndrome and explore its mechanism. Method: The adriamycin nephropathy models were established by single tranvenous injection of adriamycin (dosage 6.5 mg·kg-1). The drugs were used continuously for 21 days from the 7th day. On days 7

14

21 and 28

urine output

24 h urine protein

urinary sodium and urinary osmolality of these rats were detected. After 3 weeks of drug administration

plasma osmolality

plasma electrolyte

total cholesterol (TC)

triglycerides (TG)

albumin(ALB)

blood urea nitrogen (BUN)

serum creatinine (Cr)

and antidiuretic hormone (AVP) levels were detected

and the kidney index was calculated

antidiuretic hormone receptor 2 (AVPV2R)

aquaporin-2 (AQP2) levels in kidney and Na+-K+-ATPase activity were detected as well. At last

the expression level of AQP2 in kidney was detected by Western bolt. Result: Mori Cortex water decoction could down-regulate the level of 24 h urinary protein

improve hypoalbuminemia and hyperlipidemia

and the low dose (476 mg·kg-1) showed the best effect

30% ethanol fraction of Mori Cortex could significantly down-regulate 24 h urinary protein

TC

TG

AVP

AVPV2R

and AQP2 levels

decrease Na+-K+-ATPase activity and kidney index (P<0.05

P<0.01)

and significantly up-regulate the levels of ALB

urine output

urinary sodium and urinary osmolality (P<0.05

P<0.01). Conclusion: Mori Cortex water decoction could significantly improve the pathological symptoms of rats with adriamycin-induced nephropathy

and 30% ethanol fraction is the most effective part. Its mechanism for improving water sodium retention in Adriamycin-induced nephropathy may be associated with regulating the expression levels of plasma AVP

renal AVPV2

AQP2 and Na+-K+-ATPase activity.