OBJECTIVETo explore the effects of Huqi Extractum (HQE) on the viability and apoptosis in mouse thymic lymphocytes against 60Co radiation.

METHODSThymic lymphocytes were isolated from 4 -8 weeks healthy male Kunming mice and primarily cultured. Then they were divided into the control group, the irradiation group, the low dose HQE group, the medium dose HQE group, and the high dose HQE group. Equal volume of serum free RPMI-1640 culture solution was added in the control group and the irradiation group, while equal volume of HQE solution (at the daily dose of 25, 50, and 100 mg/mL) was respectively added in the low, medium, and high dose HQE groups. Except the control group, those in the rest groups were exposed radiation at a single dose of 5 Gy gamma-ray. Changes of the thymic lymphocytes' viability were measured by MTT colorimetric assay at 12, 24, 36, and 48 h after radiation. The early apoptosis rate was detected using flow cytometry (FCM) after 10-h radiation. The apoptosis was detected using agarose gel electrophoresis to observe the DNA injury after 24-h radiation.

RESULTSThe viability level decreased more obviously in the irradiation group than in the control group at 24 -48 h after radiation (P < 0.01, P < 0.05). The average viability level was obviously higher in the low, medium, and high dose HQE groups than in the irradiation group (P < 0.05) in a dose dependent manner. The early apoptosis rate was obviously lower in the low, medium, and high dose HQE groups than in the irradiation group, with statistical difference shown in the high dose HQE group (P < 0.01). Typical DNA ladder fragments were found in the electrophoresis in all groups except the control group. But the DNA injury was comparatively milder in the low, medium, and high dose HQE groups, with more obvious effects shown in the high dose HQE group.

CONCLUSIONHQE showed protection for the viability of early thymic lymphocytes exposed to the 60CO radiation, and could lower the early apoptosis level.