| Objective and background It has been indicated by research that under normal conditions, the target organ of heparin in the human body is vascular endothecia. But under pathological conditions, like some ischemic disease such as coronary heart disease, heparin shows more appetency to bind with ischemic vascular endothecia. And when the human body suffers some ischemic disease, large amount of vascular growth-promoting factor will be secreted by the vascular endothecia. Former research has proved that heparin show a strong tendency to bind with these vascular growth-promoting factors. After the binding of heparin and vascular growth-promoting factors, the structure of vascular growth-promoting factors in the body will be stabilized and their vascular growth-promoting function will be enhanced. Therefore, certain medicine can be developed using heparin and its derivatives to treat the ischemic disease by improving the production activity of vascular growth-promoting factors in the blood vessels.The objective of this project is to screen out certain medicine which has strong tendency to combine with ischemic vascular endothecia from several derivatives of heparin with different molecular mass and different sulfated degree. Then the ability of promoting the production of vessels of this medicine will be tested. Thus, an ideal way of treating ischemic disease could be developed.Method First, five derivatives of heparin with different molecular mass were obtained by organic solvent fractional precipitation method and hydrolysis with hydrogen peroxide. Then multi-sulfating and desulfated modification were conducted. Thecontent of organic sulfate and anticoagulation titer of these derivatives were tested. The immunohistochemistry method was employed to test the expression of vascular growth-promoting factors with the presence of aFGF and VEGF in the heart muscle ischemia of mice. Through this process, two derivatives of heparin, i.e. high molecule heparin and mean molecule heparin multi-sulfating which show the function of promoting the production of vessels were screened out. The effect of these two derivatives of heparin on the vessel production of chick chorioallantoic membrane and the healing up of the deep degree II burn wound in mice were further tested. The results proved that these two derivatives of heparin had good function of promoting the production of vessels. The double expression of aFGF, VEGF and the derivatives of heparin in the ischemic part of mouse heart muscle were tested by multiple staining.Finally the structures of these derivatives of heparin were tested using infrared spectra and magnetic resonance method and the average molecular mass of these derivatives of heparin was tested using HPLC method.Results Eight derivatives of heparin with different molecular mass and sulfated degree were prepared. Two derivatives of heparin, i.e. high molecule heparin multi-sulfating and mean molecule heparin multi-sulfating which show the function of promoting the production of vessels, were screened out using myocardial ischemia mice model. It was proved by the research of chicken chorioallantoic membrane that these derivatives of heparin had a certain function to promote the production of vessels. Also in the experiment of healing the deep degree II burn wound in mice, it was proved that these derivatives of heparin can accelerate the healing up of burn wound and shorten the time need for healing.Conclusion and significance These eight derivatives of heparin screened out by this project showed fine activity to improve the vessel growth and can be used in the treatment of ischemic disease. Although heparin itself does not have the function to promote the growth of vessels, its derivatives have the strong characteristic to bind with vascular growth-promoting factors. This binding can stabilize the structure ofvascular growth-promoting factors and improve the activity of vascular growth-promoting factors and thus help the vascular growth-promoting factors to function better. An ideal way of treating ischemic illnesses could be developed. |
