Analysis of endogenous trans-fatty acids in different tissues of beta amyloid peptide induced Alzheimer’s disease Sprague-Dawley rats
Date Issued
2010
Date
2010
Author(s)
Lan, Wen-Ann
Abstract
Trans fatty acids (TFAs) are defined as “unsaturated fatty acids that contain one or more isolated (i.e., nonconjugated) double bonds in a trans configuration.”TFAs mainly come from partial hydrogenated oil in processed foods and investigations of TFAs in the 90’s indicated that over intake of TFAs may increase the risk of cardiovascular diseases.
Besides from foods, TFAs may also be formed by free radical induced cis/trans isomerization of endogenous fatty acids from recent investigations and the formation of the “endogenous TFAs” was positively related with the amount of free radicals. Higher levels of endogenous TFAs were found in the smokers, lipopolysaccharides (LPS)-induced inflammation rats and normal aged rats. Alzheimer''s disease (AD) is the main cause of dementia. The senile plaques with beta-amyloid peptide (Aβ) and the neuron tangles are universal pathological characters of AD brain . We suspected that the higher oxidative stress and inflammation in AD brain might induce cis/trans isomerization of fatty acids. The objective of this study is to investigate if there are more endogenous TFAs in brains, livers and adipose tissues of ventriclely injected Aβ25-35 induced AD rats, and we hope that the endogenous TFAs can be an indicator of AD.
The study was divided into two parts. The first part was to analyze the oxidative biomarkers, and the second part was to analyze the fatty acid compositions of brains, livers, hearts and adipose tissues. In the oxidative biomarker analyses, liver TBARS and liver glutathione reductase (GRd) activities showed that oxidative stress may be higher in Aβ25-35 group, while plasma TBARS and glutathione peroxidase (GPx) activities were similar in all five groups.
We also analyzed fatty acid compositions of brains, livers, hearts, abdominal adipose tissue, epidydimal adipose tissue and subcutaneous adipose tissue from rats of saline (control), Aβ and ‘Aβwith resveratrol’ injection group. No TFAs were detected and fatty acid compositions were not significantly different in brains, livers, and adipose tissues from the three groups, while trace TFAs (lower than the limit of quantification)were detected in hearts. Besides, total fatty acids content in abdominal adipose tissue from Aβand Aβ with resveratrol’groups were significantly lower than the control group. We infer that the absence of endogenous TFAs might due to not sufficient free radicals induced during seven days of Aβ25-35 injection, or Aβ induced free radicals concentrated only in limited area in brain (such as hippocampus), or even the sacrifice time point was after the acute inflammation period and resulted in decreased free radicals. In the future study, we suggest to investigate the amount of free radicals induced during AD and its ability to promote the formation of endogenous TFAs.
In conclusion, no detectable levels of endogenous TFAs were found in brains, livers and adipose tissues or only trace amount of TFAs appeared in hearts from ventricle injection of Aβ25-35 induced AD rats, and the fatty acid compositions were not significantly different from the control group.
Subjects
beta-amyloid peptide
endogenous trans fatty acids
free radicals
S-D rats
gas chromatography-mass spectrometry
SDGs
Type
thesis
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