OBSERVATION OF THE SEMITHIN SECTIONS OF THE MOUSE THYMICCELL APOPTOSIS INDUCED BY DEXAMETHASONE

Objective:To obtain the time fluctuating curves of the mouse thymic cell apoptosis induced by dexamethasone. Methods: When male BALB/c mice were received an i.p. injection of dexamethasone (DEX), the mouse thymus apoptosis was induced. The thymuses were cut into the semithin sections, which were stained with the toluidine blue.The sections were examined under the oil object lens. The area of 100 mm2　was　selected to count　with the ocular microsurveyingmeter:apoptotic cell number (Ac),　apoptotic body number (Ab) and total cell number (T).According to the formula:Ac %=Ac/T, Ab%=Ab/T, the Ac percentage and Ab percentage at different time from the experimental　and the control groups were obtained. Results: Both of the peak time of apoptosis occurring in the thymic cortex and medulla were 15 h. In the cortex,the period of apoptosis ascending was 1～15 h, the period of apoptosis peak platform was 15～19 h and the period of apoptosis descending was 19～30 h. In the medulla, the period of apoptosis ascending was 1～15 h, the peak time of apoptosis was 15 h and the period of apoptosis descending was 15～30 h. Conclusion: The time fluctuating curves of Ac percentage and Ab percentage of the mouse thymic cortex and medulla offered the data for us to further study the variation of morphology of the thymic cell apoptosis and its mechanism.