Effects of Corticosterone,. cAMP, cGMP, Ca^2＋, and Protein Kinase C on Apoptosis of Mouse Thymocytes Induced by X-ray Irradiation

Objective To observe the effects of signal factors of corticosterone （CS）, cAMP, cGMP, Ca^2＋ and protein kinase C （PKC） on lymphocyte apoptosis in mouse thymus induced by X-rays of 4 Gy in vitro. Methods The DNA lyric rate for thymocytes was measured by fluomspectrophotometry. Results The DNA lyric rate for thymocytes 4-8 hours after irradiation with 2-8 Gy was significantly higher than that in the control （P〈0.01）. As compared with the control, the DNA lyric rate for thymocytes treated with 0.01 μnol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.05-0.4 μg/mL ionomycin （Iono, P〈0.05 or P〈0.01） or 0.05-0.4 ng/mL phorbol myristate acetate （PMA, P〈0.05 or P〈0.01）, respectively, was significantly increased, while the rate for thymocytes treated with 50 ng/mL cGMP was not significantly increased. The DNA lyric rate for thymocytes treated with 0.01 μmol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.2 and 0.4 μg/mL Iono （P〈0.05）, and 0.2 and 0.4 ng/mL PMA （P〈0.05） plus 4-Gy irradiation, respectively, was significantly higher than that treated with single 4-Gy irradiation, while the rate for thymocytes treated with 50 ng/mL cGMP plus 4-Gy irradiation was not increased. When both 0.4 I.tg/mL Iono and 0.4 ng/mL PMA acted on the thymocytes, the DNA lyric rate for thymocytes was significantly higher than that in the control （P〈0.01）, the DNA lytic rate for thymocytes treated with both 0.4 μg/mL Iono and 0.4 ng/mL PMA plus 4-Gy irradiation was significantly higher than that treated with single 4-Gy irradiation （P〈0.05）, but was Iono plus 4-Gy irradiation or 0.4 ng/mL PMA plus 4-Gy irradiation. can promote thymocyte apoptosis induced by larger dose X-rays. not significantly higher than that treated with 0.4 μg/mL Conclusion CS, cAMP, Ca^2＋, and PKC signal factors can promote thymocyte apoptosis induced by larger dose X-rays.

Effects of corticosterone, cAMP, cGMP, Ca2+, and protein kinase C on apoptosis of mouse thymocytes induced by X-ray irradiation

Objective To observe the effects of signal factors of eortieosterone(CS),cAMP,cGMP,Ca2 and protein kinase C(PKC)on lymphocyte apoptosis in mouse thymus induced by X-rays of 4 Gy in vitro. Methods The DNA lytic rate for thymocytes was measured by fluorospectrophotometry. Results The DNA lytie rate for thymocytes 4-8 hours after irradiation with 2-8Gy was significantly higher than that in the control(P<0.01).As compared with the control,the DNA lytic rate for thymocytes treated with 0.01 umol/L CS(P<0.01),50 ng/mL cAMP(P<0.01),0.05-0.4 ug/mL ionomycin(Iono,P<0.05 or P<0.01)or 0.05-0.4 ng/mL phorbol myristate acetate(PMA,P<0.05 or P<0.01),respectively,was significantly increased,while the rate for thymocytes treated with 50 ng/mL cGMP was not significantly increased.The DNA lyric rate for thymocytes treated with 0.O1umol/L CS(P<0.01),50 ng/mL cAMP(P<0.01),0.2 and 0.4ug/mL Iono(P<0,05),and 0.2 and 0.4 ng/mL PMA(P<0.05)Plus4-Gy irradiation,respectively,was significantly higher than that treated with single 4-Gy irradiation,while the rate for thymocytestreated with 50 ng/mL cGMP plus4-Gy irradiation was not increased.When both 0.4ug/mL Iono and 0.4 ng/mL PMA acted on the thymocytes,the DNA lyric rate for thymocytes was significantly higher than that in the control(P<0.01),the DNA lytic rate for thymocytes treated with both 0.4ug/mL Iono and 0.4 ng/mL PMA plus 4-Gy irradiation was significantly higherthanthattreatedwith single 4-Gy irradiation(P<0.05),but was not significantly bigher than that treated with 0.4ug/mL Iono plus 4-Gy irradiation or 0.4 ng/mL PMA plus 4-Gy irradiation.Conclusion CS,cAMP,Ca2 ,and PKC signal factorscall promote thymocyte apoptosis induced by larger dose X-rays.