Effect Of LA On High Fat Mouse In Lipid Metabolism And Its Mechanisms

Linoleic acid (LA) refers to naturally occurring C18 fatty acid, which have the double bond structure located in the cis at positionsΔ9, 12, of the carbon chain have been identified. A major source of LA is plant oil, Studies demonstrated LA have many biological activities including reducing blood fat, enhancing cell growth, decreasing accumulation of body fat and regulating immune function.Peroxisome proliferator activated receptors (PPARs) are a kind of nuclear transcriptional factors, belonging to the nuclear receptor super family, which exist in fat tissue and immune system. The physiological functions of PPARs protein include lipid metabolism, immune regulation and cell differentiation, Researches are shown that LA acts as ligands of PPARs to active or restrain activities of PPARs, So PPARs play an important role in modulating lipid metabolism.Lipoprotein lipase(LPL)is the key enzyme which can dispel TG to glycerin and FFA in lipid metabolism. Researches are shown that LA can change activities of LPL to achieve the balance of lipid metabolism.The experiment base on the group mouse of LA (0.4g / kg·bw) and high fat diet control, and set groups of basic control, high fat control and Simvastatin tablets(1.0mg/kg·bw)control in comparison. Through the observation of changes in body weight, serum lipids, enzymes associated with lipid metabolism, liver modality, expression of PPAR_γ, and LPL, we investigated the possible mechanisms of the effects of LA on lipid metabolism. This study will provide experimental basement for further understanding the molecule mechanisms of lipids decline of LA.As a result, (1) the effects of LA in body weight: Compared with basic control group, body weight of high fat control group is higher; Compared with high fat control group, body weight of LA control group is significantly lower; Compared with Simvastatin tablets control group, body weight of LA control group is significantly lower.(2) the effects of LA in serum lipids: Compared with basic control group, TC,TG and HDL-C of high fat control group is higher significantly; Compared with high fat control group, TC,TG and HDL-C of LA control group is lower significantly; Simvastatin tablets control group and body weight of LA control group is not different actually.(3) the effects of LA in enzymes associated with lipid metabolism: Compared with basic control group, enzymes activity of LPL, HL and total lipase of high fat control group is lower significantly; Compared with high fat control group, enzymes activity of LPL, HL and total lipase of LA control group is significantly higher; Compared with Simvastatin tablets control group, enzymes activity of LPL and total lipase of LA control group is significantly lower, enzymes activity of HL of LA control group is not different from Simvastatin tablets control group.(4) the effects of LA in liver tissue: Compared with basic control group, liver index of high fat control group is much bigger, and liver have pathological changes; Compared with high fat control group, liver index of LA control group and Simvastatin tablets control group is smaller, and pathological changes are decreased.(5) the effects of LA in expression of PPAR_γand LPL mRNA: Compared with basic control group, liver PPAR_γ, and LPL mRNA level in high fat control groups is lower; Compared with high fat control group, liver PPAR_γand LPL mRNA level in LA control groups is higher; Compared with Simvastatin tablets control group, liver PPAR_γand LPL mRNA level in LA control groups is lower.The results show that LA can reduce body weight and serum lipids level and increase activities of enzymes associated with lipid metabolism. It also decrease liver pathological changes. In the investigation of the mechanism of defending high lipids level by LA, it was indicated that LA can activate PPAR_γ, alter the expression of LPL in liver, suggesting that was associated with changes in body weight and serum lipids level. LA may impart its effect on liver lipid metabolism partly through altering the expression of LPL. However, the effects are mulriple mechanism. Therefore, it is necessary to make further study to elucidate the mechanism of LA's effects.