Systemic Metabolic Regularity Research On Mice For The Low-density Lipoprotein Receptor Knockout

This thesis investigated systemic effect research on mice for the low-density lipoprotein receptor knockout. Abnormity of lipid metabolic-related receptor or protein (LDLR or apoE knockout), high-fat, high-cholesterol diet causing atherosclerosis leads to various cardiovascular diseases. To investigate the systemic metabolic profiling associated with aetiology and development of AS, we systematically researched the time-course metabonomic changes in multiple biological matrices of LDLR’’’mice using NMR and GC-FID/MS techniques accompanied with gene expression, clinical chemistry and histopathological methods (the non-metabonomic part was done by Dan Li from Peking University). We discovered that 12-weeks high-fat/cholesterol/cholate ("western-type" diet, WD diet) treatment caused obvious aortic lesions, macrophage infiltration and collagen level elevation in LDLR-/- mice accompanied with up-regulation of inflammatory factors (aorta and liver). The WD-induced atherosclerosis progression was accompanied with metabonomic changes in multiple matrices including biofluids (plasma, urine) and tissues (liver, kidney, myocardial) involving multiple metabolic pathways. These included disruption of cholesterol homeostasis, disturbance of biosynthesis of amino acids and proteins, altered gut microbiota functions together with metabolisms of vitamin-B3, choline, purines and pyrimidines. WD treatment caused down-regulation of SCD1 (stearoyl-coenzyme A desaturase 1) and promoted oxidative stress reflected by urinary allantoin elevation and decreases of hepatic PUFA-to-MUFA ratio. When switching to normal diet, atherosclerotic LDLR-/- mice reprogrammed their metabolisms and reversed the atherosclerosis-associated metabonomic changes to large extent although aortic lesions, inflammation parameters, macrophage infiltration and collagen content were only partially alleviated. We concluded that metabolisms of fatty acids and vitamin-B3 together with gut microbiota played crucially important roles in atherosclerosis development. These findings offered essential biochemistry details for the diet-induced atherosclerosis and demonstrated effectiveness of the integrated metabonomic analysis of multiple biological matrices for understanding the molecular aspects of cardiovascular diseases.Non-steroid anti-inflammatory drugs (NSAIDS) are regularly used for anti-inflammation in the atherosclerosis therapies. These drugs inhibits the cyclooxygenase (arachidonic acid pathway) then leads to the reduction of prostaglandins. But as we know the prostaglandins materials express throughout the body and participate in many seriously important physiological roles in vivo. Thus, the usage of NSAIDS leads to severe side effects. Then we considered what metabolic response will happen if we just inhibited one receptor of prostaglandins? We chose one of prostaglandins E2 receptors (EP1) as our research object. We concluded the metabonomic changes of BALB/c mice be administered with SC-51322, a selective prostaglandins E2 receptor 1 inhibitor. We found the increased level of fatty acids decomposition, disturbance of cholesterol homeostasis, enhancement of nucleotides de novo synthesis, inhibition of gluconeogenesis and tricarboxylic acid cycle and interference of amino acids metabonome. As the models were not very strong, we used multiple univariate data analysis which illstrated the low toxicity of SC-51322. Also all of these provided the fundamental metabonomic data of EP1 and pre-clinical evaluation of SC-51322.Another work was, we found and assigned tyrosine-O-β-glucuronide in mice kidney hydrophilic extracts in the mice model using the solid phase extraction, LC-MS, one (1H,31P) and two dimensional (1H-13C, 31P-1H corresponding) nuclear magnetic resonance spectrogram combined with literatures published before.