Objective   To examine whether sodium selenite could weaken or remove the proliferative inhibition of phytohaemagglutinin(PHA)-stimulated human peripheral blood lymphocytes(PBL) induced by cispatin.

  Methods   PHA-stimulatd human PBL were incubated with cisplatin alone or in combination with sodium selenite.Cisplatin was administered to the 72 hours cultures of PBL with three different concentration(0.05, 0.20, 0.50mg/L) at 24 hours after PHA stimulation.Sodium selenite was added with a single dose of 0.05 mg/L at 0 hour or at 24 hours after PHA stimulation for different treatment.Mitotic indices(MI) of transformed lymphocytes were tested at the end of 72 hours cultures.

  Results   Sodium selenite at dose of 0.05mg/L enhanced MI of transformed lymphocytes in response to PHA stimulation by 42.8%(P < 0.05) and 13.7%(P > 0.05) above the control values when the chemical was administered respectively at 0 hour and at 24 hours after PHA stimulation.When cells were exposed to cisplatin from 0.05mg/L to 0.20mg/L, Mi of transformed lymphocytes had no significant alteration compared with control cells, however, when exposed to cisplatin at 0.50mg/L, MI was reduced by 54.5%(P < 0.001) compared to control cells.Proliferative inhibition caused by cisplatin at 0.50mg/L were counteracted and a normal MI was obtained when the cells were pretreated with sodium selenite, but when sodium selenite was simultaneously added with cisplatin, the MI inhibition by the agent could only partially enhanced.

  Conclusion   Sodium selenite at 0.05 mg/L could directly promote cell proliferation when PBL were treated with it alone.When it was used as protectant to cotreat PBL in combination with cisplatin, it can reduce cisplatin cytotoxicity, and protect PBL against the antiproliferative effect of the agent.More effective results could be obtained when it was administered to the system at the beginning of the culture.