Role Of CAMP-CREB/CREM Signaling Pathway And Its Regulation In The Injury Of Spermatogenic Cells Induced By Microwave Radiation

Objective: With the rapid development of microwave technology, its applicationbecome more and more widely in our daily life, human’s health effects of microwave radiation has attracted increasing attention. Researches show that male reproductivesystem is one of microwave radiation sensitive targets, but the molecular mechanism isunclear. Therefore, the present study is to investigate the role of cAMP-CREB/CREMsignaling pathway and its regulation in the injury of spermatogenic cells induced bymicrowave radiation, which not only may provide experimental basis for thereproduction hazard caused by microwave radiation, but also have an importantsignificance in its diagnosis and treatment.Methods:90male Wistar rats and cultured GC-2spd cells were exposed to0，10and30W/cm~2microwave for2weeks (15min/d,5d/w). The role of cAMP-CREB/CREMsignaling pathway and its regulation was explored by detecting changes ofspermatogenic cells, signaling molecules, target protein and regulatory factor of pathwayfrom6h to28d and from1h to24h respectively after microwave exposure through lightmicroscope, electron microscope, sperm class analyzer, western blot, ELISA, MTT,flow cytometry and image analysis, and so on.Results:(1) Serum testosterone levels were significantly decreased within1~3daysafter30W/cm~2microwave radiation.(2) There was a significant increase in the rate ofapoptosis and decrease in the spermatogenic cell counts of S phase at1d and7d after exposure to10and30mW/cm~2microwave. After10~30W/cm~2microwave exposure,the seminiferous tubule epithelial cells were disarrangement, the spermatogenic cellswere degeneration, necrosis, shedding, the spermatogenous cell and Leydig cell werecondensed chromatin edge, mitochondria swelling, abnormal sperm head shape, and soon.(3) The percentage of AB grade sperm, azoospermia parameters(VAP, BCF, VCLand VSL) were decreased and the percentage of C and D grade sperm were increasedat1d,14d and6h~14d after10~30W/cm~2microwave exposure. The teratospermia rateswere obviously increased at6h~1d and6h~7d after10and30mW/cm~2microwaveradiation.(4) After10and30mW/cm~2microwave exposure, the cAMP levels werereduced within7~28d, the PKA activity were increased within3~7d and decreasedwithin14~28d, the expression of CREM and p-CREB were down-regulated within6h~1d and7~14d.(5) After10and30mW/cm~2microwave exposure, the expression ofTESK1and LDH-C were down-regulated within6h~1d and7d~14d.(6) After10and30mW/cm~2microwave exposure, the expression of TORC were up-regulated within6h~28d and the expression of ACT were down-regulated within1d~7d and28d.(7)After10and30mW/cm~2microwave exposure, the cell proliferation activity ofGC-2spd were decreased within1h~24h. At6h after exposure to10and30mW/cm~2microwave, the rates of apoptosis and death were increased and the damage ofcondensed chromatin edge and cell necrosis, endoplasmic reticulum expansion inultrastructure.(8) After10and30mW/cm~2microwave exposure, the cAMP levels ofGC-2spd were reduced within6h and24h. The PKA activity of GC-2spd weredecreased within6h after exposure to10mW/cm~2microwave and increased within1~24h after exposure30mW/cm~2microwave, the expression of CREM weredown-regulated within1h~6h and up-regulated within24h, the expression of p-CREBwere up-regulated within1~24h and1~6h after exposure to10and30mW/cm~2microwave and down-regulated within24h after exposure to30mW/cm~2microwave.(9)After10and30mW/cm~2microwave exposure, the expression of TESK1were up-regulated within1h and down-regulated within6h and24h, the expression ofLDH-C were up-regulated within1h and6h and down-regulated within24h.(10) Theexpression of ACT in GC-2spd cell were up-regulated within1h and6h after30mW/cm2microwave exposure. The expression of ACT in GC-2spd cell weredown-regulated within1h and24h and up-regulated within6h after30mW/cm2microwave exposure. The expression of TORC in GC-2spd cell were down-regulatedwithin1h and up-regulated within6h and24h after10and30mW/cm2microwaveexposure.Conclusion:10and30mW/cm2microwave exposure:(1) cause decrease of serumtestosterone, damage of the spermatogenic cells and GC-2spd cells, and abnormality ofsperm parameters.(2) cause inhibition of cAMP-CREB/CREM signaling pathways,down-regulation of signaling molecules and target gene expression, which may play animportant role in the injury of spermatogenic cells.(3) abnormal expression of ACTand TORC may involve in the regulation of cAMP-CREB/CREM signaling pathways.