Study On Kinetics And Monitoring Indexes Of Exogenous Sialic Acid Intervention

Objective:The absorption,distribution and metabolism of exogenous sialic acid in the blood of mice were studied to find the possible dose-response relationship and explore the optimal dose and the shortest intervention time.Method:Male ICR mice were given exogenous sialic acid by single intravenous administration of sialic acid,single oral administration of sialic acid and continuous intragastric administration of sialic acid for 30 days.228 ICR mice were divided into four dose groups:low dose group(0.045 g/kg),medium dose group(0.090 g/kg),high dose group(0.180 g/kg)and very high dose group(0.360 g/kg).Blood was collected at 0 min,1 min,3 min,5 min,10 min,30 min,45 min,and 60 min after intravenous administration of sialic acid into mice.Blood was collected at 0 min,10 min,15 min,30 min,45 min and 60 min after a single oral administration of sialic acid into mice at different doses.After continuous gavage for 30 days,blood was collected after gavage at 0 d,5 d,15 d,20 d,30 d and fasting for 12 h,respectively.Blood was collected by eyeball extraction.After centrifugation,plasma and plasma proteins were absorbed and precipitated and erythrocyte membrane was extracted.Fluorescence spectrophotometer method was used to detect Free serum sialic acid(FSSA),Erythrocyte surface sialic acid(ESSA)and Protein-bound sialic acid(PBSA)content of mice under different way of intervention.Repeat measure ANOVA(RM-ANOVA)was used to conduct statistical analysis on the changes of sialic acid content of blood in mice by using SPSS 20.0,analyzed the variation trend and differences of different doses over time.Kinetic parameters like peak concentration(Cmax),half time(T1/2),area under curve(AUC),clearance(CL)and apparent volume of distribution(Vd)and mean retention time(MRT)were obtained by Phoenix WinNonlin 2.1 software.The results of kinetic parameters of different groups were tested by ANOVA/Kruskal-Wallis H to find possible dose-effect relationship.The Berkeley Madonna 8.3.18 software was used to construct the B-MPU multicompartment ordinary differential equation,which was used to predict changes of blood sialic acid content in mice under different intervention with different doses.Results:(1)After intravenous administration of sialic acid,the FSSA concentration of mice reached the Cmax at 1st min and returned to the basic level within 60 min.The higher the intervention dose,the higher the Cmax,the shorter the T1/2,the higher the AUC,the higher the Vd,the higher the CL,and the shorter the MRT.ESSA increased in four groups reached Cmax at 10th min,and recovered to the basic level within 60 min.The change trend was the same in four groups,and there was no statistically significant difference in Cmax,T1/2,AUC,CL,MRT among four groups(P>0.05).It was not found that the content of PBSA changed by the time after tail vein intervention.(2)After a single oral administration of sialic acid into mice,FSSA content of high dose and very high dose group increased,reached Cmax at 15th min,recovered within 60 min,changing trend is consistent in the two groups,there is no statistically significant difference in Cmax,T1/2,Vd,CL,MRT(P>0.05),but AUC of high dose group mice is higher;ESSA content increased in four groups,reached Cmax in 15th min,and recovered within 60 min.The change trend was the same in four groups,and there was no statistically significant difference in Cmax,T1/2,AUC,CL,MRT of each group(P>0.05).There was no change in PBSA content after a single oral administration of sialic acid.(3)There was no changed in FSSA content after long-term sialic acid gavage intervention.The PBSA gradually increased and reached Cmax on 20th day.The change trend was the same in different groups,and there was no statistically significant difference in Cmax,T1/2,AUC,Vd,CL,MRT in different groups(P>0.05).ESSA content of every dose group increased,reach Cmax in 15th day,the change trend of different dose was consistent,there was no statistically significant difference in Cmax,T1/2,AUC,CL,MRT of each group(P>0.05).After the long-term lavage,PBSA and ESSA change trend is consistent of four groups,we consider low dose(0.045 g/kg)as the best intervention dose.(4)The B-MPU ordinary differential equation model constructed in this study has a good fitting effect,and the key parameters of the ODE model of caudal vein are obtained as follows,K=0.43,n=0.01,a=0.24,x=1.17,y=0.08,q=0.06,r=0.01;parameters of single intragastric model are as follows,K=2.06,n=0.73,a=0.03,x=1,y=0.37,q=1.15,r=0.75;Parameters of long-term intragastric model are as follows,K=0.89,n=0.00,a=0.11,x=1.52,y=0.55,q=0.60,r=0.01.Conclusion:(1)The tissue affinity of sialic acid is low,and the metabolism of the mice is fast after a single or short-term intervention,so it is difficult to observe the effect.(2)Erythrocyte surface sialic acid and plasma protein-bound sialic acid can be used as early indicators of sialic acid.(3)Within the range of intervention dose in this study,time is the most important influencing factor,that is,the effect of sialic acid intervention on the body will not be observed until it reaches a certain time.(4)The shortest time of sialic acid intervention may be 15 days,and 0.045g/(kg·BW)can show its effect.(5)The B-MPU ordinary differential equation constructed in this paper can predict the amount of sialic acid distributed in each compartment at different doses,suggesting that the content of sialic acid in urine is a new detection index.