Studies On Dynamic Changes Of Plasma Concentrations Of Excitatory And Inhibitory Amino Acids In Patients With Intracerebral Haemorrhage

Objective: The pathophysiological mechanisms and process of peri-hematoma tissues in intracerebral haemorrhage are very complicated and many secondary injury factors occur among them. The injuries to the brain tissues come from not only the pressurization of hematoma but also impaired blood-brain barrier and active masses from the hematoma, et al. Studies for the recent years have shown that the toxicity from excitatory amino acids as an important pathological factor takes part in the developing and progressing of intracerebral haemorrhage and the disturbance between excitatory and inhibitory amino acids may be a part of it. But now the most studies about EAA and IAA are limited on in vivo studies in animals and few on clinic especially intracerebral haemorrhage but such as cerebral infarction, cerebral trauma and epilepsy, et al. By observing the dynamic changes of EAA and IAA in plasma of patients with intracerebral haemorrhage and the relation of Glu levels to hematoma size and the change of Glu concentrations following micro-wounded Surgery of intracranial hematoma, our study was to discuss the effect of EAA and IAA in intracerebral haemorrhage from clinic and to afford reference for further investigation.Methods: (1) 40 cases patients with spontaneous intracerebral hemorrhage were selected. Hematoma sizes were less than 40ml. 10 cases among them were operated with the micro-wounded surgery of intracranial hematoma in 24 hours after the onset and conservative for the rest. All of them were conscious and their vital signs were surgeless. 5ml of venous blood was drawn at 1, 3, 7 and 14 days after the onset, and then centrifuged ordinary temperature in a centrifuge tube heparinized. Plasma was separated and deproteinated and then injected into HPLC after reacted adequately with OPA.(2) Excitatory amino acids (including glutamate and aspartate) and inhibitory amino acids (includingγ-aminobutyric acid, taurine, alanine and glycine) in the standard samples and the plasma of 40 patients with intracerebral hemorrhage and 20 normal control subjects were determined by Reversed-phase high performance liquid chromatography (RP-HPLC), o-phthalaldehyde (OPA) precolumn derivatization method and fluorescence detector were used. The separation was performed using a C18-ODS column. The results of them were compared with each other. The patients who were operated with the micro-wounded surgery of intracranial hematoma compared lengthways with the conservative patients at different time point. According to the hematoma size, the conservative patients group in 1st day was divided into less than 30ml and greater than or equal to 30ml, the Glu levels were compared between them.(3) Animo acids concentrations in plasma were presented as mean±standard deviation. Two-sample t-test was used between observation group and normal control group; the ANOVA for randomized block design and SNK-q-test were used among observation groups; t-test and linear correlation were used to detect the variability between measurement datas. A statistical significance was considered for P<0.05.Results: Amino acids concentrations in the plasma of 20 healthy persons were considered as the basal value. The concentrations of Glu and GABA in the patients with ICH were increased markedly in the 1st day, peaked in the 3rd day and decreased in the 7th– 14th day called"platform period " (P<0.01); the concentrations of Asp and Tau were increased markedly in 1st day, peaked in the 7th day and decreased in the 14th day (P<0.01); The concentrations of Ala was increased markedly in 3rd day not 1st day, peaked in the 7th day and decreased in the 14th day (P<0.01); The concentrations of Glu, Asp, GABA, Tau and Ala all didn't return to normal levels in the 14th day after ICH. There was no statistics difference for the concentrations of Gly(P>0.05). The levels of Glu was significant correlated with the hematoma size (P<0.01; r=0.7568). Besides a tendency for decrease, there was no significant difference for the concentrations of Glu between the conservative patients and the micro-wounded surgery patients (P>0.05). To the former, the dominance did not detected from the latter which maybe dued to the small sample size.Conclusion: The mechanism of the toxicity of excitatory amino acids participates into the injury of peri-hematoma tissue in intracerebral haemorrhage. The plasma concentration of EAA can be considered to be an important biochemical indicator to estimate the progression of intracerebral haemorrhage; IAA can inhibit the release of EAA or resist its toxicity. The rise of GABA, Tau and Ala plasma concentrations may be a protective mechanisms; the disturbance between excitatory and inhibitory amino acids may participate into the mechanisms of the toxicity of excitatory amino acids. Because they put respectively special emphasis on the neurons, synthetically analyze the change of amino acids concentrations and interrelationship among them will further comprehend the essence of injured neuron death, and find a new way to protect the nerves.