Peony and diabetic nephropathy.
Article Type: Report
Subject: Diabetic nephropathies (Risk factors)
Diabetic nephropathies (Prevention)
Oxidative stress (Complications and side effects)
Oxidative stress (Prevention)
Medicine, Chinese (Health aspects)
Author: Finney-Brown, Tessa
Pub Date: 12/22/2009
Publication: Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 National Herbalists Association of Australia ISSN: 1033-8330
Issue: Date: Winter, 2009 Source Volume: 21 Source Issue: 4
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 215249521
Full Text: Su J, Zhang P, Zhang,J, Qi J, Wu Y, Shen J. 2009. Effects of total glucosides of paeony on oxidative stress in the kidney from diabetic rats. Phytomed. Article in press.

Paonia lactiflora is one of the most important plants in Traditional Chinese Medicine, and has been for over 1500 years. Amongst its important actions are anti-inflammatory, analgesic, antioxidative, antihepatic injury and immunoregulatory actions. Experimental studies have shown that TGP, an extract from the dried root of P. lactiflora (containing paeoniflorin, oxypaeoniflorin, benzoylpaeoniflorin, benzoyloxypaeoniflorin, oxybenzoylpaeoniflorin, albiflorin, paeoniflorigenone and lactiflorin) has nephroprotective effects in murine models of diabetes. However the mechanism has not been elucidated thus far and this was what the researchers sought in the current study.

STZ was injected into 40 male Munich-Wistar rats, inducing diabetes. The animals were then divided into four groups, three of which were treated with oral doses of TPG at 50, 100 or 200 mg/kg, whilst the fourth control group was given 0.5% sodium carboxymethylcellulose. A fifth group of normal controls was also given this placebo substance.

After eight weeks body weight was measured and urine samples were collected for measurement of albumin concentration and 24 hr urinary protein excretion. The rats were then euthanised and the kidneys removed for histological assessment.

In the diabetic rats with reduced body weight and increased glucose levels (compared with normal controls), TGP treatment had no effect on these parameters. The diabetic rats had a significantly higher ratio of kidney weight to body weight than normal animals. TGP treatment had no effect on these parameters however in diabetic rats treated with TPG, there was a dose dependent attenuation of albuminuria (experienced in the diabetic animals compared to normal controls). Despite treatment, levels of albumin in urine were still higher than observed in normal rats, indicating some levels of glomerular injury and the potential for progressive nephropathy. Renal histology displayed increased glomerular volume and tubulointerstitial damage in the rats with STZ-induced diabetes. TGP administration alleviated these changes in the treated animals.

The authors suggest that TGP counteracts elevated levels of reactive oxygen species in the diabetic rats, specifically 3-NT levels. Total antioxidant concentration, superoxide dismustase and catalase expression and activity that were reduced in the diabetic controls were significantly up regulated by the administration of 100 mg/kg and 200 mg/kg of TGP. Thus it appears that TGP (and by extrapolation Paeonia lactiflora) may protect the kidneys from diabetic nephropahtic progression by modulating and regulating oxidative stress and normalising certain key signalling pathways.

Tessa Finney-Brown MNHAA
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