AAS ›› 2013, Vol. 44 ›› Issue (4 ): 530-534.doi: 10.3969/j.issn.0529-1356.2013.04.016

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Changes of homocysteine metabolism key enzyme in insulin resistance rat model

FAN Xiao-ming1 GUO Jia-zhi1 LIU Shi-chang1 ZHANG Tie-jun1 KANG Li1 LU Di1 GUI Li 2* LI Shu-de 3*   

  1. 1. Department of Anatomy and Embryology, Kunming Medical University,Kunming 650500,China;2. Department of Endocrine, the Third Hospital of Yunnan Province, Kunming 650041, China;3. Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming 650500, China
  • Received:2012-10-17 Revised:2013-05-17 Online:2013-08-06 Published:2013-09-04

Abstract:

Objective To research the homocysteine change in an insulin resistance model for SD rats, and to discusse the molecular mechanism of the homocysteine change. Methods Twenty healthy rats, six weeks of age, were randomly divided into the control
group (n=10) and the insulin resistance group (n=10). Normal food was fed in control group;The insulin resistance model was established by high fat diet and gavaged by the high fat for 3 months. The concentrations of homocysteine, glucose, insulin,
total cholesterol and triglyceride were measured in the fasting state. At the same time, the insulin resistance index (ISI) was calculated. The expressions of methylenetetrahydrofolate reductase (MTHFR), cystathionine β synthase (CBS) and methionine
synthetase (MTR) were detected by immunohistochemistry, RT-PCR and Western blotting in the rat liver tissue. Results The concentrations of the blood glucose and blood insulin in the insulin resistance group were higher than that in the control group (P<0.05),
the insulin resistance index was increased, so the insulin resistance model was successed. The concentrations of triglyceride and homocysteine were increased (P<0.05). However, the concentration of the total cholesterol was no statistical significance
(P>0.05). The protein and mRNA expressions of MTHER and CBS in insulin resistance group were lower compared with the control group by RTPCR, Western blotting and immunohistochemical staining(P<0.05). However, the expression of MTR protein and mRNA
were not different between the insulin resistance group and the control group (P>0.05). Conclusion The homocysteine concentration is higher in the condition of insulin resistance, which may be related to decrease with the expression of MTHER and CBS in metabolic
transformation of homocysteine.

Key words: Insulin resistance, Homocysteine, Methylenetetrahydrofolate reductase, Cystathionine &beta, synthase, Methionine synthetase, Immunohistochemistry, Western blotting, RT-PCR, Rat 