Objective   To investigate the effect of excessive vitamin A and zinc intake on cell cycle of hepatocyte in normal adult rats and to identify interaction between VA and Zn.

  Methods   the rats were randomly divided into four groups(16 in each group), viz.one normal control group(received deionized water, Zn < 0.01 mg/L, C), zinc groupreceived zinc sulfate, Zn 150.49 mg/(kg·bw)of zinc sulfate, ZT, VA groupreceived retinal acetate, VA 6.27×10⁴ IU/(kg·bw)of retinal acetate, VT), and VA+Zn group(received liquid containing zinc sulfate and retinal acetate, VA 6.27×10⁴ IU/(kg·bw)of retinal acetate and Zn 150.49 mg/(kg·bw)of zinc sulfate, UT.VA or Zn was dissolved in deionized water and daily given to animals by lavaging.After two or three week supplement respective, half numbers of the group were killed.Cell cycle of hepatocyte was detected by flowcytometry.

  Results   At different time in trial, body weight, food intake and liver index were investigated, and these indexes in VT, ZT or UT were all not significantly difference compared with the contro l.Tow weeks late, different degree hydropic degeneration could be observed in every test group by optical microscope, especially thick punctate acidophilicdye area scattered occur red in VT.Continuing high dose VA or Zn or both intake, hydropic degeneration tended to be more severer in all test groups.After two week supplement, the proliferation of hepatocyte significantly increased in VT compared with the control; the increase in ZT and UT was not significant.After three week supplement, the increase in ZT was significantly observ ed, but the proliferation in VT significantly decreased and the trend depressed in UT was also observed.Further more, sub-G1 peak in individual rat occurred at different time point.At two week supplement, sub-G1 peak in VT was 1.8.At three week supplement, sub-G1 peak in VT was 1.5, and 2.1 in ZT.During the experiment, sub-G1 peak was not observed in UT.

  Conclusion   the effect of 100 times appropriate intake(AI)VA or 12 times AI Zn on cell cycle of hepatocyte is more significant than that of same dose VA and Zn both intake.