Planta Med 2005; 71(10): 917-922
DOI: 10.1055/s-2005-871248
Original Paper
Pharmacology
© Georg Thieme Verlag KG Stuttgart · New York

Crocetin Prevents Dexamethasone-Induced Insulin Resistance in Rats

Liang Xi1 , Zhiyu Qian1 , Xiangchun Shen1 , Na Wen1 , Yabing Zhang1
  • 1Department of Pharmacology, China Pharmaceutical University, Nanjing, P.R. China
Further Information

Publication History

Received: December 22, 2004

Accepted: April 8, 2005

Publication Date:
04 August 2005 (online)

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Abstract

The main objective of the study was to examine whether crocetin, a natural product from Gardenia jaminoides Ellis, has beneficial effects on the state of insulin resistance induced by dexamethasone in a rat model. Measured using the oral glucose tolerance tests (OGTT), male Wistar rats treated with subcutaneous dexamethasone (0.08 mg/kg/d) for 6 weeks exhibited reduced insulin sensitivity at weeks 2 and 4 and impaired glucose tolerance at week 4. In the dexamethasone-treated group, serum insulin, free fatty acids (FFA), triglyceride (TG) and tumor necrosis factor (TNF)-α levels were significantly increased at the end of the study. In addition, the hepatic glycogen content was reduced as indicated by periodic acid-Schiff (PAS) staining, and pancreatic islet β cells showed compensatory hyperactivity suggested by immunohistochemical (IHC) staining using an antibody against insulin. Treatment with crocetin (40 mg/kg/d) significantly attenuated all the described effects of dexamethasone. These results suggest that crocetin might prevent the development of dexamethasone-induced insulin resistance and related abnormalities in rats.

Abbreviations

AUC:area under the curve

CON:control

CRO(H):high-dose crocetin

CRO(L):low-dose crocetin

CRO:crocetin

DEX:dexamethasone

FFA:free fatty acids

GAUC:area under the glucose curve

HE:hematoxylin-eosin

IAUC:area under the insulin curve

IHC:immunohistochemical

ISI:insulin sensitivity index

MET:metformin

OGTT:oral glucose tolerance test

PAS:periodic acid-Schiff

TG:triglyceride

TNF:tumor necrosis factor

References

Zhiyu Qian

Department of Pharmacology

China Pharmaceutical University

P.O. Box 46

24 Tongjia Xiang

Nanjing 210009

People’s Republic of China

Phone: +86-25-8327-1322

Fax: +86-25-8327-1355

Email: trueqianzhiyu@yahoo.com.cn