Studies On Protective Effects Of Baicalin On Mice Injured By Ionizing Radiation

Radiation therapy is the indispensable means of treatment for cancer patients, but it also induced the declination of hematopoietic and immune function of patients and affected the treatment effects, someone are even forced to terminate effective treatment.How to improve the effect of radiotherapy and protect normal tissue has been an urgent problems to be resolved. With the development of medical radiology, drug therapy research of radiation injury has made great progress. Western medicines have obvious protective role in radiation injury, however, its clinical application was restricted because of their toxicity. Chinese medicines have become increasingly drug research focus of radiation protection field because of its wide source,low toxicity, broad role and many Chinese medicines today have been identified as having the role of radiation protection.The main mechanisms of anti-radiation function of Chinese medicine was protective effect for DNA, hematopoietic system, immune system and effect of anti-free radicals and inhibiting lipid peroxidation reactions.Chinese baicalin is a famous traditional Chinese medicine, dry root of Labiatae plant Scutellaria, perennial plant roots, and has trentment effects for the upper respiratory tract infections, urinary system infections, dysentery, hepatitis, hypertension,ect. Baicalin is the main active ingredient of Scutellaria root, it has pharmacological effects of antibacterial, anti-inflammatory , chelating metal ions, anti-allergic, scavenging free radicals and anti-tumor.Protective effects of pre-treated bacicalin on irradiated mice were studied in this dissertation, and the possible mechanism was approached with a view toprovided theoretical support for the development of new radiation protection drugs.130 Kunming mices with weight in 18g²0g, half male and half female, were randomly divided into three groups after normal feeding three days:negative control group, positive control group and protection group. Distilled water was given to mice of control group and different concentrations of bacicalin(50 mg·kg^-1,100mg·kg^-1 and 200mg·kg^-1) was given to mice of protection group once a day. Mice in positive control group and protection group were exposed to one-time whole-body x-ray after 15 days. WBC and GSH-PX in blood, spleen and thymus index, SOD and MDA in liver, MN in PCE of bone marrow were detected at 72h after irradiation.1. Effect of baicalin on peripheral blood leukocyte in mice exposed to X-rayPeripheral blood leukocytes in mice exposed to X-ray decreased and there was statistically difference between negative control group and positive control group (P<0.01), the higher radiation dose, WBC reduction was more obvious. After mice pro-treated by different dose baicalins were exposed to 2.0Gy X-ray, peripheral blood leukocytes increased obviously, and were statistically different compared with the positive control group (P<0.05 or P<0.01), and there was a dose-response relationship; only 3.0Gy X-ray, peripheral blood leukocytes increased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.05 or P<0.01); for only 4.0Gy X-ray, peripheral blood leukocytes increased in high dose protection group and was statistically different compared with the positive control group (P<0.05 or P<0.01). Certain dose baicalin can inhibit peripheral blood leukocyte reduction induced by irradiation and has protective effect on the hematopoietic damage induced by radiation.2. Effect of baicalin on spleen and thymus index in irradiated miceSpleen index : Spleen index in mice exposed to X-ray decreased and there was statistically difference between negative control group and positive controlgroup(P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy X-ray, spleen index increased obviously, and were statistically different compared with the positive control group (P<0.01); for 3.0Gy and 4.0Gy X-ray, spleen index increased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.05 or P<0.01).Thymus index : Thymus index in mice exposed to X-ray decreased and there was statistically difference between negative control group and positive control group(P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy X-ray, thymus index increased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.01); for 3.0Gy and 4.0Gy X-ray, thymus index increased in high dose protection group and was statistically different compared with the positive control group (P<0.01). Certain dose baicalin has protective effect on spleen and thymus ,could enhance immune function, and there was a dose-effect relationship.3. Effect of baicalin on blood GSH - Px activity in irradiated miceBlood GSH - Px activity in mice exposed to X-ray decreased and there was statistically difference between negative control group and positive control group(P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy and 3.0Gy X-ray, GSH - Px activity in blood increased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.05 or P<0.01);for only 4.0Gy X-ray, GSH - Px activity in blood increased in high dose protection group and was statistically different compared with the positive control group (P<0.05 or P<0.01). Experimental results suggested that certain dose baicalin can upgrade GSH - Px activity in blood of mice exposed to X-irradiation.4. Effect of baicalin on SOD activity and the content of MDA in liver of irradiated miceSOD: SOD activity in liver of mice exposed to X-ray decreased and there was statistically difference between negative control group and positive control group(P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy, 3.0Gy and 4.0Gy X-ray, SOD activity in liver increased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.05or P<0.01).Experimental results suggested that certain dose baicalin can inhibit degradation of SOD activity radiation-reduced in liver.MDA: The content of MDA in liver of mice exposed to X-ray increased and there was statistically difference between negative control group and positive control group (P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy X-ray, the content of MDA in liver decreased in medium and high dose protection groups and was statistically different compared with the positive control group (P<0.05);for 3.0Gy and 4.0Gy X-ray, the content of MDA in liver decreased in high dose protection group and was statistically different compared with the positive control group (P<0.05 or P<0.01). The experimental results suggested that a certain dose of baicalin has a suppressive effect to lipid peroxidation of irradiated mice.5. Effect of baicalin on micronuclei in PCE of bone marrow in irradiated miceMicronuclei in PCE of mice exposed to X-ray increased and there was statistically difference between negative control group and positive control group(P<0.01). After mice pro-treated by different dose baicalins were exposed to 2.0Gy, 3.0Gy and 4.0 Gy X-ray, micronuclei decreased obviously, and were statistically different compared with the positive control group (P<0.05 or P<0.01). Certain dose of baicalin can protect chromosome from damage induced by radiationThe experimental results showed that certain dose baicalins could inhibit radiation damage induced by X-ray, play a protective role on irradiated mice andthere was a certain dose-effect relationship, the mechanism may be related to the removal of free radicals.