Artificially Modified Porcine Hemoglobin And Its Application, A Preliminary Study

Hemoglobin, when it is departed from Ted Mood ceR, hag- ui^y '''smKiV'MEi1 such as structure instHbility, high uxygeu affinity, short half-life and kidney toxiciiy. As a \xtechnology, chemical modification of hemoglobin has been applied to improve these poor characteristics of the hemoglobin. Stroma-free porcine hemoglobin(SFH) was separated and purified from fresh pig blood by centrifugation and filtration with 0.45 to 0.22 u m films. ThenSFH was modified by t^^;^aMCTiinsa|^yl)-6immteg3^^of pH7J2 ?37 TC and deoxygenater for 2 hoars: The^ derivative of-DBBF^cross^Bnked hemoglobin(DBBF-pHb) showed the special character to resist the dissociation of a 2 P 2 tetramer in comparison with natural protein. DBBF-pHb was then bound to the activated PEG which was based on its reaction with N-hydroxysnccinimide(NHS), resulting in a stable tetramer pHb dcribative with a lager molecular weight and well oxygen-carrying capacity.Rabbit was immunized with SFH, DBBF-pHb and mPEG-DBBF-pHb respectively. Compared with DBBF-pHb, mPEG modified DBBF-pHb markedly reduced the immunogenecity by 75% (1 :800 and 1 3200, respectively).The protective effects of DBBF-pHb and mPEG-DBBF-pHb on isolated myocardial tissue were evaluated from the point of myocardial ultrastructure analysis. In experiments groups, the isolated myocardial tissues were perfused with Krebs-Henseleit solution containing DBBF-pHb and mPEG-DBBF-pHb respectively. In control group, the isolated myocardial tissue was perfused with Krebs-Henseleit solution. There were significant differences among three groups. The myocardial ultrastructure injuries were greater in control group. The DBBF-pHb and mPEG-DBBF-pHb could offer great protective effects on preservation of the isolate hearts. In the retransfusion animal model, when transfusion capacity is 15%, the fraction surviving of rabbits is 100%. The effect of transfusion of DBBF-pHb on the capacity of lactate dehydrogenase(LDH) is very evident Equal volumes of SFH, DBBF-pHb and mPEG-DBBF-pHb were compared for their ability of reverse the effects of hemorrhagic shock, hi the recovery period of DBBF-pHb, the mean arterial blood pressure(MAP) was increased from 30 mmHg to 107 mmHg after 5 minutes and men decreased gradually. In the 60-minute recovery period of mPEG-DBBF-pHb, MAP maintained 106 mmHg, which had not significant difference from control values.