Effect of morphine and electro-acupuncture (EA) on apoptosis of thymocytes

The influence of morphine and EA on the apoptosis of thymocytes were studie d to investigate the posibility of its involvement in the mechanism of morp hine-induced immunosuppression and the regulatory effect of EA on it. Ih af ter injecting 50 mg/kg morphine subcutaneously into 3-wk old Balb/c mice co ntinually twice a day for 5 days, thymus was collected and the apoptotic ce ll was detected by a method of terminal deoxynucleotidyl transferase-medita ed dUTP nick end-labeling(TUNEL). The results showed that morphine signific antly enhanced the percentage of TUNEL positive cells inside thymus with an appearing of apoptotic DNA ladder after 24 h incubation. Treating mice wit h EA of "Zusanli(St.36)" and "Lanwei(Ext.33)" for Ih after morphine adminis tration decreased the percentage of TUNEL positive cells. EA also showed an regulatory effect on the increased the expression of CPP32 and decreased t he expression of Bcl-2 by morphine. The significant enhancement of hypothal amic CRF and plasma ACTH level by morphine and the antagonize effect of EA on it suggested a possible role of Hypothalamus - pituitary - adrenal (HPA) axis played in the apoptosis of thymocytes by morphine and the regulatory effect of EA.