Radiation exists throughout cosmic space and is divided into two categories: ionizing radiation and non-ionizing radiation. In the field of nuclear energy, people are mainly concerned about the possible health effects of ionizing radiation and its protection. Ionizing radiation is usually referred to as radiation or radiation exposure. Radiation includes electromagnetic radiation and particle radiation, and can be divided into radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and γ-rays and other radiation according to frequency and wavelength.
I. Ionizing radiation
Ionizing radiation is increasingly widely used, has been developed into various disciplines. In medical imaging diagnosis on the application of a long time ago, and is still progressing, radiation therapy has also been developed into a medical science, in the treatment of tumors has an irreplaceable role; radiation is used for vegetables, medical supplies, proprietary Chinese medicines and cosmetics and other sterilization, as well as automobile tires and heat-shrinkable plastics production; in the industry is also used for the determination of the thickness, levels and temperatures to achieve the industrial automation, the integrity detection of industrial products, namely industrial CT; radiation is also used to determine the thickness, levels and temperatures to achieve industrial automation, industrial products. Integrity testing of industrial products that is industrial CT; radiation can also deal with food to prevent crop germination, kill pests and pathogens, etc..
At the same time, some high radioactive background material such as granite in large quantities, and even nuclear power plant leakage and the outbreak of nuclear war and other unforeseen factors, may make the residents suffer from radiation damage. Therefore, the study of efficient and low-toxic radiation protection (protection) agent is particularly important.
Two, non-ionizing radiation
Non-ionizing radiation is weaker than the energy of ionizing radiation. Non-ionizing radiation will not ionize the material, but will change the molecules or atoms of the rotation, vibration, or valence layer of the electronic track state. The effects of non-ionizing radiation on living biological tissues are beginning to be studied. Different non-ionizing radiation can produce different biological effects. First, the role of the principle of radiation
Biological in vivo experiments have proved that: radiation has a direct effect and indirect effect of two kinds of radiation, the direct effect of radiation is a radioactive source of energy or particles directly deposited in a variety of biological and cause biological ionization and excitation, destruction of the body's nucleic acids, proteins and enzymes, and other substances with the function of life; indirect effect of radiation is the first action of radiation on the water, and the decomposition of the reaction products and biological macromolecules to have an effect, resulting in the biological function of radiation. The indirect effect of radiation is that radiation first acts on water, and its decomposition reaction products interact with biological macromolecules, causing physical and chemical changes in biological macromolecules. The water content accounts for 80% of the dry weight of living organisms, so the influence of indirect action is crucial for living organisms. The radiolytic products of water are mainly free radicals, which have two main mechanisms of action. Radiolytic products of water, free radicals, play a very important role in the indirect effects of radiation damage, they and biomolecules can occur between the following types of reactions: hydrogen extraction reaction, substitution reaction, electron capture reaction, addition reaction, disproportionation reaction and peroxidation reaction of Sichuan. Therefore, most of the reactions initiated by free radicals can be completed within a few seconds after irradiation. However, some free radicals can generate new free radicals uninterruptedly for several days.
Two, radiation damage to DNA
While the difference between direct and indirect effects can be distinguished under experimental conditions, the two effects often co-exist in living cells, and in fact are complementary. The two actions are of roughly equal importance in killing cells, inhibiting DNA synthesis, and inducing chromosomal aberrations by radiation. The direct action may be important in the occurrence of radiation damage to DNA because the proteins (histones) surrounding the DNA molecule are protective against the damaging effects of free radicals.DNA damage is thought to be a major factor in cellular lethality. Free radicals are necessary for the maintenance of life during normal life processes. However, free radicals are also potential killers of biomolecules, cells and biological tissues. Under normal physiological conditions, free radicals can be maintained in a dynamic equilibrium at a normal physiological level. Once the balance is disturbed and the number of free radicals increases, pathological changes can be caused.
Mutagenic effects
Base changes, gene deletions and DNA sequence rearrangements and even changes in gene expression can cause mutations yob. Certain oxidation products are hidden in the DNA molecule and become a mutagenic hazard that is not easily recognized by the DNA repair system. In the late mitotic phase of the cell when chromosomes regularly enter the daughter cell to form the nucleus, the chromatid monomers or unattached fragments or loops of chromosomes that remain in the cytoplasm form one or more regular subnuclei individually after the terminal phase and are contained in the cytoplasm of the daughter cell to form a micronucleus.
Lethal effect radiation interferes with DNA repair, radiation acts on hydrated deoxyribonucleoproteins and interferes with DNA replication and transcription processes! Chuan, nuclear membrane replication in vivo enzymes are damaged, affecting the cellular repair process!}' -1; excessive depletion of gluten skin camp skin (GSH) in vivo makes Ca- ten balance imbalance, these may lead to cell death.
Cell cancer
Radiation cancer has long been a clear conclusion, and DNA is the target of the action, whether it is carcinogenic or promote cancer are free radicals involved, and thus potentially carcinogenic higher. It can stimulate the body's immune function under certain conditions. According to the report of UNSCEAR in 1986, after irradiation with high dose (more than 2Gy), it causes humoral immune damage reaction at the initial stage, and after a certain latency period, along with the secondary reaction of radiation damage, the body is in an extremely complicated and chaotic state. The death of highly sensitive cells produces debris, releasing factors, intestinal endotoxins, and stimulation of external sources of infection cause antibodies to enhance the development of response, and some antibody formation function may be hyperactive so that the level of IgA} IgG or IgE increases and may last for several weeks, and the body shows obvious immunosuppressive effects. How far is radiation from us? Radiation is everywhere in our living environment!
Household appliances: TV, refrigerators, air conditioners, microwave ovens, vacuum cleaners, computers, etc. Office equipment: cell phones, computers, copiers, electronic instruments, medical equipment, etc.
Home decoration: marble, laminate flooring, wallpaper, paint, etc.
Surrounding environment: TV (radio) signal towers, nuclear radiation, etc.
Natural environment: sunspots and so on.
Transportation: airplanes, trains, high-speed rail Electromagnetic radiation pollution has become the fourth major environmental pollution following water, air, noise. If one day, you live in the house was suddenly told in the more serious electromagnetic radiation, how would you? Anti-radiation research, generally refers to the organism is subjected to ionizing radiation to give some kind of chemical substance to block the indirect effect and reduce its radiation damage, and promote its recovery, that is, chemical protection or drug protection. Radiation protection drug research is mainly the following from several aspects:
1, free radical scavenging or passivation
Radiation indirect effect is mainly free radicals involved, scavenging free radicals is the focus of radiation protection research.
2. Protection of vital substances
The synthesis and release of these endogenous substances are stimulated by drugs, or enzymes or enzyme protectants are given directly with radiation protection. Ionizing radiation first damages important biological macromolecules, which in turn affects cellular function and then causes overall biological effects. Many studies have shown that Ryukyl compounds form disulfides with biological macromolecules to make them less radiosensitive and thus protected from attack. Superoxide dismutase (SOD), GSH peroxidase, catalase, etc., constitute the body to remove a large number of free radicals generated in the body due to oxidative stress.
3, to prevent or reduce the long-term effects
For the protection of the direct effect of radiation, in addition to mechanical shielding means, can also use nuclear egg-white and other substances on the protection of DNA, or DNA itself structure of the sensitivity of radiation damage to the differences in radiation damage to consider the protective effect of the drug on the radiation, but also through the drug on the radiation-induced cancerous genes and inhibition of cancerous gene It can also reduce the occurrence of DNA mutation and cell cancer to a certain extent through the regulatory effect of drugs on radiation-induced cancerous genes and cancer-suppressing genes, and promote the normal repair of DNA. thereby improving the body's ability to resist radiation.
4, bee venom peptide anti-radiation
A large number of domestic and foreign studies show that bee venom has anti-radiation effect. 1968, Ginsberg reported that bee venom anti-radiation effect is statistically significant, bee venom can make the survival rate of animals subjected to 800 roentgen radiation increased from 40% to 100%. Artyomov confirmed that bee venom injections have a protective effect against radiation, as well as a therapeutic effect. 1970 Iwao Miyano of Osaka, Japan, used cobalt as an irradiation source, confirming that bee venom has an anti-T-rays effect. The main effect of the radiation protection effect of bee venom is to cause a neuroendocrine response and enhance the body's anti-radiation effect. The use of bee venom peptide instead of bee venom whole venom not only has a preventive effect on radiation, but also has a therapeutic effect.