pharmacodynamics
1. Effect on blood
Hirudin can prevent thrombin from acting on fibrin and hinder blood coagulation. Hirudin will not be destroyed by heat or ethanol. Leeches can also secrete a histamine-like substance, which can dilate capillaries and increase bleeding. The alcohol extract of leech has stronger inhibitory effect on blood coagulation than tabanus and peach kernel, and the alcohol preparation of leech has stronger effect than water preparation. 20mg hirudin can prevent 100g human blood coagulation.
Leech water extract has obvious inhibitory effect on ADP-induced platelet aggregation in rats and normal people, and has antithrombotic effect.
The results showed that leech had a strong fibrinolytic effect in vitro, and its activity was significantly higher than that of salvia miltiorrhiza and rhubarb. It also has fibrinolytic activity in vivo, which can significantly shorten the euglobulin lysis time (ELT) of rabbits. So leeches can activate the chemical fiber dissolving system and dissolve thrombus. It has also been reported that hirudin can obviously inhibit experimental thrombosis and dissolve experimental venous thrombosis caused by thrombin.
Leech water extract can reduce the specific viscosity of whole blood and plasma in rats. Shorten erythrocyte electrophoresis time. Clinical research shows that leech can improve the concentration, viscosity and aggregation of patients with ischemic cerebrovascular disease caused by abnormal hemorheology.
2. Effects on cardiovascular system
It is reported that leeches can increase myocardial nutrient blood flow to some extent; It has protective effect on tissue ischemia and hypoxia. Hirudin can antagonize the coronary artery spasm caused by pituitrin in rabbits and has the therapeutic effect of inhibiting myocardial ischemia. Leech can obviously eliminate atherosclerotic plaque, make collagen fiber proliferate in plaque and reduce cholesterol crystallization. It is suggested that leeches have potential application value in the prevention and treatment of atherosclerosis.
Leech can dilate capillaries, improve microcirculation and increase renal blood flow. Its effect on improving microcirculation is similar to heparin, but its action time is short. Experiments show that leech can dilate peripheral blood vessels, increase blood flow and reduce vascular resistance, which is similar to papaverine hydrochloride.
3. Effect on pregnancy
Experiments show that leech can terminate the pregnancy of mice at all stages (including implantation and early, middle and late pregnancy). Different routes of administration have a good termination effect on early pregnancy. If exogenous progesterone and leech are injected at the same time, premature delivery can be prevented. Leech has inhibitory effect on decidual lesions.
4. Other functions
Leech can obviously reduce cholesterol and triglyceride in experimental hyperlipidemia rabbits.
Hirudin can inhibit the growth of tumor cells and mouse liver cancer. Because leech has high anticoagulant effect, it is beneficial for anticancer drugs and immunocompetent cells to infiltrate into cancer tissues and kill cancer cells.