| Objective:Evaluate the therapy of extracorporeal whole blood immunoadsorption on experimental allergic neuritis and access the mechanism of cellulose-tryptophan on the adsorption.Methods:For optimize the immunogen of EAN rabbits,myelin basic protein (MBP)was extracted from bovine sciatic nerve.The New Zealand rabbit EAN model was induced by intradermic injection of MBP or bovine sciatic nerve.The healthy rabbits were divided into four groups,i.e.experimental group one(treated with immunoadsorption for one time at the day 14 after immunization),experimental group two(underwent immunoadsorption twice,at the day 14 and the day 16 after immunization),positive control group(EAN rabbits without any treatment)and negative control group(physiologic saline solution instead of MBP and underwent immunoadsorption at the same time with group two).According to Graham K,the clinical manifestation of the EAN rabbits was graded in 7 levels.The blood samples were taken from the rabbits before and after therapy for the assessment of the biocompatibility.To the negative and positive control groups,the electrophysiological functions,including motor nerve conduction velocity(MNCV),motor evoked potential amplitude,F wave were evaluated at the day 18 after immunization.All the rabbits were comprehensively examined,e.g.electrophysiological function and pathological changes,at the day 35 after immunonization.ELISA was introduced for the measurement of serum P2 protein antibody.The blood samples for the detection of P2 protein antibody were regularly drawn from all the rabbits,from the day 0 to the day 60 after immunization.F(ab')~2,Fab,and Fc fragments of IgG from the health rabbits were achieved by pepsin and papain,for the further investigation on the mechanism of cellulose-tryptophan.Results:EAN was successfully induced either by MBP or sciatic nerve.EAN rabbits set up by the sciatic nerve undertook the extracorporeal whole blood immunoadsorption.In positive control group,symptoms climbed to the climax from the day 28 to the day 32,remitted from the day 35.00±0.63,and the mean duration was 60.80±0.84 days.The rabbits in the experimental group one developed the neurological signs of EAN at the day 14.25±0.46,ameliorated since the day 32.13± 0.64,the duration is 42.38±0.50.The experimental group two,rabbits recovered at the day 30.25±0.46,the duration is 38.38±0.52.The perivascular infiltration of macrophages and demyelination in the sciatic nerve were found in positive control group.Experimental group showed lighter pathological changes,especially in experimental group two.The positive control group,at the day 18,MNCV retarded obviously,amplitude fell down,the detection rate of F wave reduced and the electrophysiological function continued to deteriorate until the day 35.Compared with positive control group,the electrophysiological function in the experiment groups significant improved(p＜0.05).Anti-P2 IgG could be detected at the day 5 post-inoculation and plasma levels showed a sharply rise and gradual fell down throughout the experimental period in positive control group.No significant changes of blood cells,electrolytes and blood lipids were found.Serum albumin was not altered by adsorbent,but the concentration of globulin dropped down.The adsorption rate of F(ab')~2 and Fc was 17.94±4.10%and 2.48±2.63%,no adsorption was observed with Fab.Conclusion:Imunoadsorbent with cellulose as carrier tryptophan as ligand was biocompatible with the blood system and had specific affinity with Globulin.It was inferred that cellulose-tryptophan most likely bond with the hinge region of IgG. Compared with positive control,experimental group displayed less severe clinical sign,faster recovery of electrophysiological and pathological characteristics of sciatic nerves.Based on these results,it can be concluded that extracorporeal whole blood immunoadsorption has therapeutical effect on EAN rabbits.
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