Effects And Mechanism Of Sparassis Latifolia Polysaccharides On Cholesterol Metabolism In Rats With High Fat And High Cholesterol Diet

[Objective] The study aims to explore the effects and mechanism of Sparassis latifolia polysaccharides on cholesterol metabolism in rats with high fat and high cholesterol diet,and to provide theoretical basis for the development of Sparassis latifolia polysaccharides functional products.[Methods] Fifty 6 weeks old healthy female mice were randomly divided into five groups,and named as normal control group(NC group),high fat and high cholesterol model group(HFCM group),high fat and high cholesterol +low dose group(HFC+LD group),high fat and high cholesterol +middle dose group(HFC+MD group)and high fat and high cholesterol +high dose group(HFC+HD group).The experimental groups were given 100,200 and 400 mg/kg·bw·d polysaccharides solution respectively,and the NC group and the HFCM group were given the same amount of saline.After 8 w,whole blood was collected and serum was prepared for the serum metabolic indexes(TC?TG?LDL-C?HDL-C and TBA),antioxidant indexes(SOD?T-AOC?CAT?GSH-Px?MDA)and the differential components of serum.Liver was also collected.Liver index was measured,and liver structure was observed by HE staining.The liver metabolism indexes(TC?TG?LDL-C?HDL-C and TBA)and the antioxidant indexes(SOD?T-AOC?CAT?GSH-Px and MDA)were also measured.q RT-PCR was used to detect the expression of HMG-Co A R?SOAT1?CYP7?-1?PPAR??ABCA1?LCAT and SR-BI m RNA expression in the liver.[Results](1)The results showed that there was no significant difference in body weight and food intake among the groups.Compared with NC group,the TC?LDL-C and TBA contents of serum in HFCM group were increased significant or extremely significant(P<0.05 or P<0.01).The HDL-C contents were significant decreased(P<0.01).T-AOC?GSH-Px?CAT and SOD activities were significant decreased(P<0.01).MDA contents were increased significantly(P<0.01).Compared with HFCM group,the TC and LDL-C contents of serum in HFC+HD group decreased significantly or extremely significant(P<0.05 or P<0.01).The CAT activities of HFC+HD group increased significantly.T-AOC activities in dose groups increased significantly or extremely significant(P<0.05 or P<0.01),GSH-Px and SOD activities increased significantly or extremely significant(P<0.05 or P<0.01).The MDA contents of each dose group decreased and the differences were significant or extremely significant(P<0.05 or P<0.01).(2)11 differential metabolites were screened from the serum of the NC and HFCM groups.Compared with NC group,the metabolites in the serum of the group were mainly upregulated by phenylalanine,methionine,propionate and valine and mainly downregulated by 1,5-dehydrated sorbitol,alanine,glycine,proline,glutamate,serine and threonine.14 differential metabolites were screened from serum of HFCM group and Sparassis latifolia polysaccharides group.Compared with the HFCM group,the metabolites in the serum of Sparassis latifolia polysaccharides group were upregulated by pentanoic acid,tyrosine,glycerol,glycine,threonine,serine,alanine,and succinate and downregulated by urea,pyrimidine,glucose,cholesterol,palmitate,and isoleucine.Through the analysis of metabolic pathway,the metabolism of cholesterol was regulated mainly by 7 metabolic pathways,in which glutamic acid and glutamine had the most influence.(3)Compared with NC group,the liver index of the HFCM group was significantly increased(P<0.01);The liver was pale in color and rough in surface,the liver lipid droplets increased,the fat vacuoles increased and the swelling degree increased;The TC?TG and LDL-C contents increased significantly(P<0.01),and HDL-C contents decreased significantly(P<0.01);the SOD,GSH-Px,and T-AOC activities decreased and the differences were extremely significant(P<0.01).Compared with the HFCM group,the liver index of dose groups decreased and the difference was not significant;The liver got red and had smooth surface;Less lipid droplets,less vacuoles and less swelling can be seen in the liver;The TC and TG contents decreased significantly or extremely significant(P<0.01 or P<0.05)in HFC+HD group,The LDL-C contents decreased and the TBA contents increased,and the differences of HFC+MD and HFC+HD group were extremely significant(P<0.01).(4)Compared with NC group,The m RNA expression of HMG-Co A R and SOAT1 were significantly increased(P<0.01)and the m RNA expression contents of CYP7?-1,PPAR? and ABCA1 significantly decreased(P<0.05).Compared with HFCM group,the m RNA expression contents of HMG-Co A R and SOAT1 in the HFC+MD and HFC+HD groups decreased,in which the differences were significant or extremely significant(P<0.05 or P<0.01).In HFC+HD group,and the m RNA expression contents of CYP7?-1 and ABCA1 increased,among which the difference was significant(P<0.05).[Conclution] Sparassis latifolia polysaccharides can decrease serum TC and LDL-C contents,liver TC?TG and LDL-C contents and increase liver TBA contents.It can improve serum and liver antioxidant activities and protect liver.It may improve cholesterol metabolic disorder in high-fat and high-cholesterol diet rats by regulating glutamate and glutamine metabolism,valine,leucine and isoleucine synthesis,glycine,serine and threonine synthesis,phenylalanine,tyrosine and tryptophan synthesis,alanine,aspartic acid and glutamate metabolism,arachidonic acid metabolism,and glycerophospholipid metabolism.Sparassis latifolia polysaccharides can inhibit HMG-Co A R and SOAT1 m RNA expression,promote CYP7?-1 and ABCA1 m RNA expression,reduce the synthesis of endogenous cholesterol,promote cholesterol transport,inhibit cholesterol absorption,accelerate the conversion of cholesterol to bile acids,and ultimately play a role in improving cholesterol metabolism in serum and liver of high-fat and high-cholesterol diet rats.