Research On The Protective Effect And Mechanism For The New Type Protective Materials On The Injury Induced By Microwave Radiation

ObjectiveExcessive microwave radiation can cause damages to human beings, especially to thebrain and reproductive system. Among many protective measures, wearing protectiveclothing is the most direct and effective personal protection method. This study intended toestablish an animal model of microwave radiation-induced injures of brain andreproductive system, to observe the effects of different protective clothing materials formicrowave radiation induced brain and reproductive damage and to lay the foundation forthe practical application and research of new microwave protective materialMaterials and Methods90male Wistar rats were randomly divided into six groups: sham radiation group(Group C), radiation alone group (Group R), stainless steel fiber fabric protection group(Group B), silver fiber fabric protection group (Group Y), the new shuttle woven fabricprotection group (Group W), and a new knitted fabric protection group (Group N).Microwave at the power density of30mW/cm2were used to expose rats for15min. All ratsin protection groups were placed in the radiation box and then put into the radiationprotection pocket made by respective protective material (1m×1m). The sewing threadswere the silver plated wire. The openings of the pocket were made of silvered surfacefastener. Rats in group C were placed in the radiation box without microwave radiation.The new woven and knitted fabrics were made of the silver fiber and cotton wovenfabrics. The spectrum analyzer was used to evaluate the shielding effectiveness of the twofabrics. The digital printing technology was used to stain the new woven fabric samples.Morris water maze was applied to test of the ability of learning and memory of rats. HPLCassay was used to analyze the content of Asp, Glu, Gly and GABA in hippocampus. Thestructure of rat hippocampus and testicular tissue was observed by the optical microscopyand electron microscopy. The expression of SYN Ⅰin the hippocampus was detected bywestern blot. Colorimetric method was used to detect the content of ATP in thehippocampal and testicular tissue. The levels of serum testosterone were detected by the radioimmunoassay. By the same time, we counted the deformity rate of epididymal sperm.Results1. The development of two new types of protective materials(1) The results of shielding effectiveness: In the range of10MHz~40GHz, theshielding effectiveness of the new type woven fabrics was≥52.6dB, which can be shieldedmore than99.99945%of the microwave radiation; the shielding effectiveness of the newtype knitted fabrics was≥40.1dB, which can be shielded more than99.99023%of themicrowave radiation.(2) Color: The camouflage was chosen for the new type woven fabrics, while thecolor of silver-plated fiber itself was selected for the new type knitted fabrics.2. Protective effects of two kinds of new materials on the brain injury in ratsinduced by microwave radiation(1) The changes of the rats’ learning and memory abilities: Compared with groupC, the average escape latency of group R and B was significantly increased at6h~7h after30mW/cm2microwave radiation (P <0.01or P <0.05). The average escape latency of groupY, W and N was significantly shorter than that of group R (P <0.01or P <0.05). At14dafter radiation, the average escape latency of group W was lower than group R (P <0.05).At28d after radiation, there was no significant difference on the average escape latencyamong all groups (P>0.05).(2) The changes of the content of Asp, Glu, Gly and GABA in the rats’hippocampus: At7d after radiation, compared to group C, the levels of Glu/GABA ingroup R and B were significantly increased (P <0.01or P <0.05), the levels of Glu/GABAin group Y, W and N had no significant difference (P>0.05). At14d after radiation, thelevels of Glu/GABA of each group had no significant difference (P>0.05).(3) Histological changes in the rats’ hippocampus: At7d after radiation, obvioushippocampus damages were observed in group R, such as, the loose structure ofhippocampus, chromatin condensation of some neurons and the widened pervascular space.The damage level of group B was less than group R. The neurons occasionally showedchromatin condensation in group Y, W and N. Moreover, the perivascular space waswidened in group Y, M and N. At14d after radiation, the above damages were reduced.The injuries nearly recovered to normal at28d after radiation.(4) Ultrastructural changes in the rats’ hippocampus: At7d after radiation, nuclearmembrane of neurons and synaptic clefts were blurred, and the perivascular space waswidened in group R. The damage of group B was less than group R. The ultrastructure of group Y and N were close to normal, while group W was normal.3. Protective effects of two kinds of new materials on the reproductive systeminjury in rats induced by microwave radiation(1) The changes of the rats’ serum testosterone: At7d after radiation, the rats’serum testosterone levels of group R and B were significantly reduced (P<0.01). Thelevels of serum testosterone in group Y, W and N were close to group C. At14d and28dafter radiation, there were no significant differences of rats’ serum testosterone among thesix groups (P>0.05).(2) The changes of sperm malformation rate of the rats’ epididymis: At14d afterradiation, compared with group C, the sperm malformation rates of group R and B weresignificantly increased (P <0.01or P <0.05). Compared with group R,the spermmalformation rates of group Y, W and N were low, but compared with group C, there wereno significant differences (P>0.05). At28d after radiation, the sperm malformation ratewas decreased, and without significant differences among the six groups (P>0.05).(3) Histological changes in the rats’ testis: At7d after radiation, spermatogenic cellsof group R were lumpish. Changes of histological structure in group B were similar togroup R. Protein edema fluid was accumulation in the seminiferous tubule of group Y andN. The histological structure of group W was normal. At14d after radiation, histologicalchanges in the rats’ testis were decreased. The injuries recovered nearly at28d afterradiation.(4) Ultrastructural changes in the rats’ testis: At7d after radiation, mitochondrialstructure of spermatogonia in group R was blurred, the nuclear membrane gap ofspermatocyte and some spermatid were widened, some sperm head shape were abnormal,nuclear membrane of stromal cells were blurred. The damage of group B was less thangroup R. Spermatogenic cells and sperms in group Y, N and W were normal.4. The mechanism for protective effect of two kinds of new protective materialson the injury induced by microwave radiation(1) The changes of the content of ATP in the rats’ hippocampus and testis:Compared with group C, at7d after radiation, the content of ATP in the rats’ hippocampusand testis in group R and B were significantly reduced(P <0.01). Compared with group C,there was no significant decrease of the content of ATP in group Y, W and N (P>0.05). At14d after radiation, the content of ATP of each group had no significant difference (P>0.05).(2) The changes of the expression of SYN Ⅰin the rats’ hippocampus: Compared with group C, at7d after radiation, the expression of SYN Ⅰin group R and B wassignificantly reduced (P <0.01). However, the expression of SYNⅠin Group Y, W and Nhad no significant decrease (P>0.05). At14d and28d after radiation, the expression ofSYN Ⅰhad no significant difference among the six groups (P>0.05).Conclusions1. The study developed two new protective materials. In the range of10MHz～40GHz,the shielding effectiveness of the new type woven fabrics was≥52.6dB.The shieldingeffectiveness of the new type knitted fabrics was≥40.1dB.2.30mw/cm2microwave radiation could injure the rats’ hippocampus and testis,which was displayed as the rats’ learning and memory abilities decreasing, amino acidsneurotransmitter metabolism disorder in hippocampus, chromatin condensation in someneurons, synaptic structure injury; decreased serum testosterone, increased rate of spermmalformation, spermatogenic cells and sperm injury.3. The different types of protective materials had protective effects on the brain andreproductive damages caused by microwave radiation. Among these materials, the newtype of woven fabrics had the best protective effect, the silver fiber fabrics and the newtype of knitted fabrics had the better protective effect, stainless fiber fabric had not obviousprotective effect.4.30mw/cm2microwave radiation could reduce the expression of SYN Ⅰin rat brainand the content of ATP in brain and testis, the different types of protective material mayantagonize these changes caused by microwave radiation, and the new type of wovenfabrics had the most significant effect.5. The protective effect of different materials was achieved by antagonizing theexpression of SYN Ⅰreduction in brain and the content of ATP reduction in brain andtestis, which induced by microwave radiation.