Effect Of Lysine Intake On Metabolic Kinetics Of Immunoglobulin G Marked By ²H₂O In Rats

PurposeThere is currently no reference for intakes of essential amino acids for Chinese people,and relative studies are few.In the previous studies of our team,we have preliminarily got the requirement of dietary lysine for Chinese healthy young men through experiments.To further verify if the requirement actually satisfies the population’s physiological requirements,we intend to perform the present study including relationship between Lysine intakes and IgG metabolic kinetics of rat’s plasma to solve the problems.Lysine intake too low or too high is a question whether to affect the IgG of body,whether has the difference compared to normal lysine intake.It provides the basis to further analysis of this group of early results whether human lysine requirements really satisfy the human physiological needs.MethodsBy intraperitoneal injection of deuterium of Rats to tag samples,after 90 min we observed whether IgG combining deuterium in the blood.Gradient elution method was used to determine the best purified IgG,which was identified by sds-page.Derivated Ala of hydrolyzed IgG and detected by GC/MS.In the condition of daily diet,rats intake three different feed that respectively contents High(1.6%),Normal(0.9%),Low(0.2%)levels lysine.Heavy water is used as the indicator to label rat’s protein with isotope deuterium in vivo by Saline(preparation of D20).ip and adding 4%D2O of daily drinking water.Study three groups of rat’s blood of IgG metabolic kinetics and Fractional synthesis rate of IgG.To analysis the sensibility about serum immunoglobulin G kinetics index to lysine intake.We will establish system of detection method for further researching more sensitive indexes about lysine intakes,finally,lays a foundation to determine Lysine requirements for human body.ResultsThe gradient elution method was used to determine the best IgG purify strategy(inclued buffer concentration,pH,flow rate and time)and the sds-page evaluated the best condition to get the best capacity and purity.GC/MS experiments showed that the heavy water injected in intraperitoneal of rats in 90 min can mark alanine of the hydrolysate of serum IgG in a short time.It means that heavy water mark alanine detection method has established successful.The third chapter experiments showed that three groups of rats body weight and food intake have significant differences,from big to small in turn:the High dose group,Normal dose group,Low dose group.There are significant differences in level of IgG,TP between High dose group and Low dose group(P<0.05).High dose group of level of IgG and TP is the highest,and then followed by normal dose group,low dose group.With the increase of lysine intake,serum IgG synthetic score rate showed a trend of increase.IgG synthetic dynamic equation:High dose group ft = 0.076027×(1-e-0.2231t),Normal dose group ft = 0.084139×(1—e-0.1483t),Low dose group ft = 0.10620×(1—e-0.1051t).The synthetic dynamic curve shows that with the increasing of lysine intake,2H-alanine abundance of rat plasma IgG is on the decline and has shorter time to steady-state.ConsultsLow doses of lysine can obviously reduce the rats’ weight and food intake and it can reflect the effects on the weight of rats in a short period of time.Low dose group of serum IgG lysine content and TP content were significantly lower than the high dose of lysine group.With the increase of lysine intake,the plasma IgG synthetic score rate is increasing and the steady-state abundance is falling.In a conclusion,the rat’s plasma IgG score rate of synthesis and synthetic dynamic equation is higher sensitive to lysine intake.