ABSTRACT
<p><b>OBJECTIVE</b>To observe the inhibitory effects of crescent euphorbia on tumor growth, immunoregulation, the side effect on the mice blood system, cell cycle and to investigate its effect on apoptosis of tumor cells.</p><p><b>METHOD</b>Crescent euphorbia was administered gastrally to C57BL/6J mouse implanted with Lewis lung cancer for 12 days. Inhibition on tumor growth, immunoregulation,the side effect on the mice blood system and cell cycle were observed and its effect on apoptosis of lung cancer cells were investigated.</p><p><b>RESULT</b>(1) Inhibitory rates of crescent euphorbia at doses of 7.5, 15, 30 g x kg(-1) and 60 g x kg(-1) were 0.61%, 16.93%, 32.81% and 58.26% respectively, significant differenel with those of controls at doses of 30 g x kg(-1) and 60 g x kg(-1)(P < 0.05). (2) Although no effect on thymus index in normal mouse at all dose of crescent euphorbia was found, spleen index in tumor-bear mice was reduced significantly at dose of 60 g x kg(-1)(P < 0.05). (3) No side effect on the miceblood system was found. (4) The percentage of S phase of cell cycle was increased in the group of crescent euphorbia at dose of 30 g x kg(-1), 60 g x kg(-1) and the apoptotic rate was (16.43 +/- 18.69)% and (24.37 +/- 15.48)% by flow eytometry (P < 0.05). The apoptotic index (AI)of these two groups were (4.00 +/- 7.50)% and (5.93 +/- 5.96)% by TUNEL, however apoptosis was found in the group at doses of 60 g kg(-1) (P < 0.01).</p><p><b>CONCLUSION</b>Crescent euphorbia can inhibit the growth of Lewis lung cancer in mice, no side effection for the mice blood system and the effect might be associated with induction of apoptosis on cancer cells.</p>