| Objective and significance: Along with the development of science and technology,microwaves are widely used in various fields, such as military affairs, medical treatment industry, and daily life, which make microwave radiation pollution become new and important environmental factors, the potential hazards them bring to human health has drawn more and more concern of all circles. Studies have confirmed that microwave radiation on certain conditions bring vary degrees of damage to the nervous system, immune system, cardiovascular system and reproductive system etc. However, the prevention and treatment of microwave radiation damage is mainly in physical shielding and absorption, there’s little drugs which has significant effect and high safety. Besides, the damage mechanisms of microwaves have not been elucidated, there are still a lot of controversy.Sulfated polysaccharides from brown seaweeds(SPS),whose full name is the seaweed polysaccharide sulfate, is extracted from Chinese herbal medicine(kelp), it’s a high molecular polysaccharide polymerized with sulfated fucose. Previous studies showed that sulfated polysaccharide can scavenge hydroxyl radicals and superoxide anion radicals, enhance antioxidant activity and decrease MDA content significantly. This product is extracted from natural materials, it has many advantages, such as non-toxic side effects, high safety, low price of raw materials, easy to extract and use, which has a broad application prospect.Materials and methods:(1) SPS is extracted using the water extraction and alcohol precipitation method. We used gas chromatography to analysis the content of total sugar. Molish Test, barium sulfate precipitation and ninhydrin test to qualitative analysis the total sugar, sulfate and protein. Phenol sulfuric acid method, Barium sulfate turbidimetric method and Lowry method to quantitative detection the content of total sugar, sulfate and protein content.(2) 210 healthy adult male Wistar rats were randomly divided into 7 groups: the normal control group, the HPM radiation group, the low dose group, the middle dose group, the high dose group, the positive drug group and the middle dose control group.The drug groups were intragastric administration one time per day seven days before radiation until seven days after radiation. The normal control group and the HPM radiation group were orally given equal volume of saline. We sacrificed rats to take blood, brain and testis at 1d, 3d, 7d after the withdrawal of the medicine. We tested the blood routine, CD3+, CD4+, CD8+ lymphocyte subsets and other immune indexes, XOD, MPO, SOD,CAT, GSH-px, MDA,PCO and other oxidative damage related indexes. The change of pathological morphology of hippocampus and testis were observed by light and electron microscope.Results:(1) The SPS sample we extracted by water extraction and alcohol precipitation is in accordance with the quality standard.(2) During the drug administration, comparing the normal control group, the radiation group and the administration group at the same time, the weight of rats showed no obvious change.(3) Comparing with the normal control group, HPM radiation significantly reduced the white blood cells and lymphocyte counts and significantly increased the content of CD3+, CD4+ in the 1st day after drug withdrawal. The content of the white blood cells was still significantly reduced in the 3rd day after drug withdrawal. Comparing with the HPM radiation group, the lymphocyte counts(1st day after drug withdrawal) and the white blood cells counts(1st and 3rd day after drug withdrawal) of the middle dose group and the white blood cells counts of the positive drug group were significantly increased.(4) In brain, comparing with the normal control group, HPM radiation significantly reduced the activity of SOD(1st to7 th day after drug withdrawal), significantly increased the activity of XOD(1st day after drug withdrawal) and MPO(1st and 3rd day after drug withdrawal), significantly increased the content of MDA(1st to 7th day after drug withdrawal) and PCO(1st day after drug withdrawal). XOD(1st day after drug withdrawal), MPO(1st day after drug withdrawal), MDA(3rd and 7th day after drug withdrawal) and PCO(1st day after drug withdrawal) in the middle dose group, the high dose group and the positive drug group were significantly reduced. MPO(3rd day after drug withdrawal) and MDA(1st day after drug withdrawal) in the low dose group were also significantly reduced.(5) In testis, comparing with the normal control group, HPM radiation significantly reduced the activity of SOD and CAT, significantly increased the activity of XOD and MPO, significantly increased the content of MDA and PCO in the 1st day after drug withdrawal. In the 3rd day after drug withdrawal, the activity of SOD and CAT were still significantly reduced, the MDA content were still significantly increased. Comparing with the HPM radiation group, MPO(1st day after drug withdrawal), MDA(3rd day after drug withdrawal) and PCO(1st day after drug withdrawal) in the low dose group were significantly reduced. SOD(1st day after drug withdrawal) and CAT(1st day after drug withdrawal) were significantly increased, MDA(1st and 3rdday after drug withdrawal) and PCO(1st day after drug withdrawal) were significantly reduced in the middle dose group, the high dose group and the positive drug group.(6) Histological observation showed that HPM radiation induced hippocampal neuron karyopyknosis, anachromasis, edema and widen the perivascular spaces. Edema can be observed in the perimeter of the seminiferous tubule germ layer. The ultrastructure observation showed that HPM radiation induced edema in hippocampal neurons and glial cells, mitochondria swelling and cavitation. Swelling and cavitation can also be observed in the mitochondria of spermatocyte and sperm cells. Comparing with the HPM radiation group, the injury in the administration groups were reduced to a different extent, especially in middle dose group, the injury was significantly reduced.Conclusion:(1) 30 m W/cm2 HPM can lead to different degree of oxidative stress injury in the brain and testis of rats, and lead to immune function decreased.(2) Different doses of SPS can reduce the immune function damage,brain and testis oxidative damage induced by HPM radiation. The 50mg/kg/d SPS group can significantly increase the lymphocyte counts and the white blood cells counts, it can also relieve the brain and testis morphology damage induced by HPM radiation. The 25mg/kg/d SPS group can inhibit the rise of XOD, MPO, MDA and PCO in testis induced by HPM radiation, and increase the activity of SOD and CAT in brain. The 50mg/kg/d SPS group can inhibit the rise of XOD, MPO, MDA and PCO in brain and testis induced by HPM radiation, and increase the activity of SOD and CAT in brain and testis. The 100mg/kg/d SPS group can inhibit the rise of XOD, MPO and MDA in brain and testis induced by HPM radiation, and increase the activity of SOD and CAT in brain and testis. The effect of low dose drug treatment is not as well as the middle dose group and the high dose group, the effect of middle dose drug treatment is almost the same as the high dose group. Thus, the middle dose of SPS is more suitable for the prevention and treatment of oxidative stress induced by HPM radiation. |
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