| The key points of atherosclerosis formation are lipoprotein dysfunction, endothelial damage and inflammation. TFA contributing to atherosclerosis is also intrigued by these factors. Epidemiologic studies have demonstrated that TFA has the negative impacts on blood lipid (raising LDL-C and TG as well as lowering HDL-C) and increases inflammation and endothelial damage.The content, category and distribution of fatty acid in fat molecular are the important factors in determining the absorption, metabolism and function of lipid. Fatty acid position in triglyceride affects velocity of lipoprotein clearance and then influence triglyceride metabolism directly. However, TFA position analysis in fat molecular of tissue has not yet been reported.The present study designed a laboratory rodent diet simulating the Chinese dietary, in which fat accounted for 33% of total energy; TFA made up 8% of total energy in all experimental groups; oleic acid, linoleic acid and linolenic acid in group 1,2 and 3 represented 6% of total energy, respectively. Group 4 was control group with reasonable fatty acid ratio (n-6/n-3=4.38) and group 5 was the control group with saturated fatty acids mainly containing palmic acid. As a result, it was explored that how TFA and other functional fatty acids interacted to affect lipid metabolism in rats.The main research results were as follows:1. The intake of TFA can arouse metabolism disfunction of blood lipid in rats, increasing TG and lowering HDL-C. All experimental groups were based on equal intake of TFA, among which groups with higher PUFA, especially group 3 and 4 added linoleic and linolenic acid, increased HDL-C/TC, HDL-C/LDL-C as well as the activity of LPL and HL; these index in group 4 (n-6/n-3=4.38) grew more markedly. However, groups with SFA and higher oleic acid had no effects on LPL and HL activity. Compared with LDL-C and HDL-C seperately, the indexes of HDL-C/ TC and HDL-C/LDL-C were better in evaluating comprehensive cholesterol metabolism of blodd lipid. There is no variance of CRP and blood sugar among the experimental groups. 2. The intake of different ratio functional fatty acid and TFA altered tissue fatty acid composition of rats. The trend between tissue and dietary fatty acid was basically consistent. Because of functional and metabolic differences of tissue, fatty acids composition in erythrocyte membrane and fat tissue were more similar to that in diet. TFA contents in brain, heart, kidney, intestine, liver, erythrocyte membrane, muscle, spleen and fat tissue were 0.35%,7.32%,7.33%,1.56%,7.69%,8.60%,8.82%,9.19%,13.45%, which indicated that variances of TFA metabolism and accumulation existed among different tissues and fat tissues were more capable of storing TFA. Perhaps oleic and linolenic acid had competition effects on suppressing TFA deposit and linolenic acid may function through producing oleic acid. The effect of linoleic acid on TFA was little while SFA promoted TFA deposit.3. The fatty acid position varied between TG of dietary vegetable oil and animal tissue. In TG of rat tissue, SFA, trans-18:1, EPA, DPA and DHA preferred to distribute in sn-1,3-TG while 18:1n-9,18:2n-6 and 18:2n-3 in sn-2-TG and almost all 18:2n-6 in sn-2-TG In vegetable oil, unsaturated fatty acids mainly containing 18:1n-9,18:2n-6 and 18:2n-3 contributed in sn-2-TG; SFA content in sn-1,3 far outweighed that in sn-2-TG.4. TFA content in TG exceeded that in PC and PE. In TG of rat tissues, TFA mainly accumulated in sn-1,3-TG but TFA in sn-2-phospholipids. The distribution feature of TFA was similar to SFA but the degree of variance is lower than SFA, which was in accordance with the rule that the chemical characteristics of TFA were between SFA and unsaturated fatty acids. The TFA content trend of position in different test groups kept consistent. However, different structural fatty acids affected a little on TFA deposition in liver and intestine tissue.5. PUFA content accumulated in PC and PE of intestine and the content of PUFA in PE far outweighed that in PC; PUFA content of liver among TG, PC and PE have little variance. SFA and MUFA accumulated in sn-1 of PC and PE in liver and intestine of rats whereas PUFA in sn-2. |
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