Primary Investigation Of The Relationship Between The Size Of ?-1,4 And ?-1,3 Glucuronic Acids Oligomcrs And Their Neuroprotective Activity

Background:Ischemia stroke is a neurological disease which is the major cause of death and adult disability worldwide,with high incidence,high mortality,high disability rate,causing a heavy social and financial burden to the sufferers and their families.Recombinant tissue-type plasminogen activator(rt-PA)is commonly used in clinic,however,due to the narrow ' therapeutic window'(<4.5 h)and reperfusion injury induced by rt-PA,only 3-5%of patients currently benefit from rt-PA therapy.So it is urgent to explore new drugs that can extend the 'therapeutic window' or promote neurological function recovery after ischemia stroke.?-1,4 and ?-1,3 oligo-glucuronic acids are prepared successfully.Previous oxygen and glucose deprivation(OGD)experiments have showed that the cell viabilities of oligo-glucuronic acid treated are higher than model.However,both of the ?-1,4 and ?-1,3 oligo-glucuronic including at least 8 fractions.Considering that the glycosyl configuration,connection mode and degree of polymerization of oligo-glucuronic acid may affect its neuroprotective activity,so determining the structure-activity relationship between its structure and neuroprotective activity is of great significant for the development of similar drugs.Objective:To compare the protective effect of the glycosyl configuration,connection mode and degree of polymerization on HT-22 nerve cell injury induced by OGD;To describe the structure-activity relationship of neuroprotective effects of glucuronic oligosaccharides and find active oligosaccharide fragments.Methods:Obtained ?-1,4 and ?-1,3 oligo-glucuronic with the degrees of polymerization of two to eight by gel permeation chromatography and strong anion exchange chromatography.Compared different oligo-glucuronic acids neuroprotective effects on HT-22 neuronal injury induced by OGD.The protection mechanism of oligo-glucuronic acids was preliminary examined by fluorescence quantification.Results:1.Obtained ?-1,4 and ?-1,3 Oligo-glucuronic with the degrees of polymerization of two to eight by the methods of gel permeation chromatography and strong anion exchange chromatography.Ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q/TOF-MS)was used to identify the structure and purity of the samples.The data showed that the samples were of high purity and could be used in activity experiments.2.The HT-22 neuroprotection effect of ?-1,4 and P-1,3 oligo-glucuronic acids from dp2-dp9 showed an increase in the degree of polymerization,especially heptasaccharide,octasaccharide and nonasaccharide can significantly reverse the neuronal damage caused by OGD.Besides,?-1,4 oligo-glucuronide acids are better than ?-1,3.3.Treatment of different OGD time,P-1,4 and ?-1,3 oligo-glucuronic acids can protect HT-22 from neuronal damage,?-1,4 and ?-1,3 heptasaccharide,octasaccharide,and octasaccharide had the most obvious protective effects in dose-dependent.4.?-1,4 and ?-1,3 oligo-glucuronic acids with high degree of polymerization can reverse the increase of ROS and the reduction of ATP in HT-22 nerve cells caused by OGD.Conclusions:The above results showed that oligo-glucuronic acids with the same basic constituent units but different linkage bond cause different neuroprotective activities,?-1,4 oligo-glucuronic acids are better than ?-1,3,and oligo-glucuronic acids with high degree of polymerization can significantly reverse the increase of ROS and the reduction of ATP in nerve cells caused by OGD.This study provides a reference for the purification of oligo-glucuronic acids,the structure-neuroprotective activity relationship and mechanism of neuronal protection,to some extent,provides directions for drug development of anti-stroke diseases.