Effect Of Electromagnetic Pulse Irradiation On Genital System And Its Mechanism

In this study.characteristic of pathological changes,injury regularity of testis and its mechanism were explored systemly at the cellular,sub-cellular and molecule level,through long-term,dynamic,many parameter observation after mice irradiated generally by 8×103V/m,2×104V/m and 6×104V/m electromagnetic pulse (EMP)respectively for five times,effect of 6×104V/m EMP irradiation on pregnancy,growth and development of offspring, and reproduction function affected by occupational exposure was initially observed.The main results are as follows:1. Characteristic of pathological changes and injury regularity of testis after EMP irradiation(1) Three kinds of field strength EMP irradiation may cause severe non-thermal structural injury of spermatogenic cell in mice,sperm, spermatids and spermatogenous cells are the most sensitive cells.Pathological changes have quick, phase, persistent and discordant characteristic,and positive relate to field strength.(2) Concentration of serum testosteone,expression of androgen receptor proteir and mRNA in testis significantly decrease in early and middle phase after three kinds of field strength EMP irradiation (but there are not obvious changes in serum follicle-stimulating hormone,luteinizint hormone,estradiol,and expression of follicle-stimulating hormone receptor in testis),and Leydig cells occur a series of obvious organizational and ultrastructural changes,it suggests Leydig cells is one of the most susceptible cells.2. Mechanism of testis injury induced by EMP irradiation(1) Increase of apoptotic cell counts is confirmed by TUNEL staining at 28 day,7d~14d and 3d~28d,expression of bax mRNA, bax,p53 and c-fos protein also significantly increase at 28d,3d~7d and 6h~28d respectively after three kinds o EMP irradiation(P<0.05 or P<0.01),but expression of bcl-2 protein significantly enhance transiently at ld~3d.lt shows that apoptosis is important mechanism which testicular cell injury induced by EMP irradiation.(2) Increase of content of malondialdehyde and expression of tumor necrosis factor-a,but decrease of activity of superoxide dismutase within 28 days after three kinds of EMP irradiation,which suggest oxygen-derived free radidicals and cytokines take part in testicular structural and functional injury induced by EMP irradiation.(3) Ativity of lactate dehydrogenase,succinate dehydrogenase,glutamate dehydrogenase and sorbitol dehydrogenase all decline differently in 14 days,especially decline significantly in 7 days,and blood supply of testis decrease,The results suggest that ischemic-hypoxia and disturbance of energy metabolism in spermatogenic cells may play important in spermatogenic cell early injury induced by EMP irradiation .(4) Leydig cell membrane appeared immediately much electroporation after 6×104V/m EMP irradiation for five times,and recovered gradually from 30min to one hour.Compared with controls,there are obvious changes of ionic concentration at different time,and significant decrease in testosteone concentration from 24 hour to 48 hour in culture medium after irradiation. The results suggest that electroporation of cell membrane may be one of the important non-thermal effect mechanism of EMP irradiation.3. Effect of EMP irradiation on pregnancy,growth and development of offspringFemale and male Kunming mice (6~8 weeks old) prior to copulation, or pregnant mice were total body irriadiated by 6× 104V/m EMP for five times,there are effect on pregnancy,growth and development of offspring, which displays decrease of body weigh and tail length of live foetus,increase of femal offspring ratio, increase of fetal death rate and embryo absorption rate.4. Effect of electromagnetic irradiation on reproduction of occupational populationReproduction function of 169 occupational personnels in certain radar inspection station of Guangxi is found by epidemiological survey,exposure of male population to microwave caused decrease in serum testosteone, increase in sexual disfunction and increase in girls ratio of offspring,female population exposure to microwave appeare abnormal menstruation and increase in girls ratio of offspring,which all correlate with exposure strength and working lifetime.It suggests that long-term and low-level exposure to microwave may have an effect on reproduction function of male and female population to some extent.