| Polygonati Rhizoma is a common plant of medicinal and food homologous,which mainly contains polysaccharides,saponins,alkaloids and other chemical components.Among them,polygonatum sibricum polysaccharides（PSP）is one of the main active components.Research shows that PSP has pharmacological activities such as liver protection,antioxidant and immunoregulation.Lead（Pb）and cadmium（Cd）are common pollutants in Guizhou,which have great harm to human health.Studies have found that a small amount of Pb and Cd accumulation can cause different degrees of damage to the body.At present,metal chelators,nutrients and vitamins are often used in clinical treatment,but there are large side effects,so it is urgent to develop new therapeutic agents.Our previous study found that PSP had a better protective effect on liver injury caused by Pb and Cd combined with heavy metals,but its pharmacodynamic characteristics and related mechanism were unclear,which hindered the further development and utilization of PSP.Therefore,based on the pollution of Pb and Cd in Guizhou,this study explored the protective effect of PSP,in order to depth evaluate its pharmacodynamic characteristics and explore the mechanism of action,and provide scientific reference for clinical treatment of liver injury caused by Pb and Cd and the deep development and utilization of PSP.In this work,the hot water extraction was used to optimize the extraction conditions of PSP by single experiment combined with response surface analysis,and then the purification was carried out,and its physical and chemical properties were analyzed to clarify the basic chemical composition.On this basis,the liver injury model of Pb and Cd compound heavy metals was established by intragastric administration.Systematic pharmacodynamic evaluation was carried out from the basic behavioral characteristics,body weight and organ index,blood routine,AST and ALT levels of liver tissue and pathological sections of liver tissue of mice in each group.The pharmacodynamic characteristics of PSP against liver injury caused by Pb and Cd compound heavy metals were basically clarified.Finally,the anti-liver injury mechanism of PSP was explored from the perspectives of traditional oxidative stress target and untargeted lipidomic.In this work,the pharmacodynamic characteristics and mechanism of PSP on liver injury induced by Pb and Cd combined heavy metals were evaluated in depth,so as to provide a scientific basis for the treatment of liver injury induced by Pb and Cd combined heavy metals.The main research results are as follows:1.Polygonatum sibiricum was cut into thick slices,broken into coarse powder and defatted.Through single factor investigation,response surface analysis and combined with the actual situation,the optimal extraction process of PSP was obtained as follows:solid-liquid ratio 1:22 g?m L-1,time 2 h,temperature 72 oC.Three parallel experiments were carried out to verify that the extraction rate of PSP was21.00±0.03%,which was close to the predicted value of the model,indicating that the model was reliable.PSP was extracted by the best method,and the yield was2.08%.After purification of PSP,the polysaccharide content of PSP was 64.70%;Then PSP was extracted from the physical and chemical properties.The protein content was 1.45%,the glucuronic acid content was 0.30%,and the monosaccharide mainly contained Man,Glc,Gal and Arb,and also contained a small amount of Rha and Glc A.The main molar ratio was 76.4:8.9:2.8:1.2.The above results can basically explicit the composition of PSP,and establish foundation for the subsequent Pb and Cd compound heavy metal induced liver injury.2.Objective to explore the effect of PSP on liver injury induced by Pb and Cd in KM mice.After 5 weeks,the body weight of mice in PSP treatment group was increased,the heart organ index was increased,and the liver and kidney organ index was decreased.At the same time,the expression of AST and ALT in liver tissue was decreased（P<0.05）,and the number of red blood cells（RBC）was increased.The pathological observation of liver tissue showed that the cell necrosis,arrangement and vacuolar degeneration of liver tissue in PSP group were improved,indicating that PSP had a good effect on liver injury induced by Pb and Cd combined with heavy metals.3.By detecting the oxidation indexes in liver tissue,the results showed that the activity of GSH-PX in liver tissue was decreased in the Pb and Cd model group（P<0.05）,SOD,LDH activity and MDA content were increased.The results showed that the activity of SOD,LDH,GSH-PX and MDA in the PSP group were decreased,which indicated that PSP could reduce oxidative stress response by reducing SOD,LDH activity and MDA content to improve the antioxidant activity of the body.4.Lipid metabolism in liver tissues of mice in each group was analyzed by untargeted lipidomics.The results showed that 24 differential lipid metabolites were screened out in the blank group and the Pb and Cd model group,including 4 Fatty acyl（FA）,13 Glycerophospholipids（GP）,4 Prenol Lipids（PR）and 3 Sphingolipids（SP）.It was found that PSP could regulate the metabolic disorder caused by lead and cadmium combined with heavy metals.Compared with the Pb and Cd model group,three kinds of Phosphatidylcholine（PC）,Lysophosphatidylethanolamine（LPE）,Ginkgolide B and Sphingosine-1-Posph-ate in the PSP treatment group were up-regulated,three kinds of Phosphatidylethanolamine（PE）,two kinds of Lysophosphatidylethanolamine（LPE）,SM,Bexarotene and Abietic acid were down-regulated,and the differential lipid metabolites tended to the blank control group.Pathway analysis of 24 screened differential lipids showed that they were mainly related to linoleic acid metabolic pathway,sphingolipid metabolic pathway and glycerol phospholipid metabolic pathway.The results showed that PSP could regulate lipid metabolism disorder caused by heavy metals of lead and cadmium,which might be regulated by linoleic acid metabolism pathway,sphingolipid metabolism pathway and glycerolphospholipid metabolism pathway.This study provides a theoretical basis for the development of potential therapeutic reagent for clinical treatment of liver injury caused by lead-cadmium combined with heavy metals and the deep development and utilization of PSP. |
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