In this paper

effect of fast-neutron and X-rays on the expression of P53 and CyclinB1 in small intestinal tissues of mice were investigated. The mice were randomly grouped and sacrificed 6 h after irradiation. Western blot assay was applied to detect the p53 and CyclinB1 expressions

and flow cytometry was used to monitor changes in the small intestinal cell cycle. The results showed that the expression levels of p53 increased with irradiation dose. The expression levels of CyclinB1 increased with the dose at first

but decreased when the dose exceeded 0.28 Gy. The results from the flow cytometry showed that the amount of cells in G2/M phase increased with the dose in both occasions. It was concluded that the low doses of fast-neutron and X-rays can make the expression levels of p53 and CyclinB1 increase

but the expression levels of CyclinB1 decreased and the G2 arrest occurred with increased doses.