AIM: To detect the effect of acid fibroblast growth factor (aFGF) on P53 and P21WAF-1 expression in rat intestine after ischemia-reperfusion (I-R) injury in order to explore the protective mechanisms of aFGF.METHODS: Male rats were randomly divided into four groups, namely intestinal ischemia-reperfusion group (R),aFGF treatment group (A), intestinal ischemia group (I),and sham-operated control group (C). In group I, the animals were killed after 45 min of superior mesenteric artery (SMA) occlusion. In groups R and A, the rats sustained for 45 min of SMA occlusion and were treated with normal saline (0.15 mL) and aFGF (20 μg/kg, 0.15 mL),then sustained at various times for up to 48 h after reperfusion. In group C, SMA was separated, but without occlusion. Apoptosis in intestinal villi was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling technique (TUNEL).Intestinal tissue samples were taken not only for RTPCR to detect P53 and P21WAF-1 gene expression, but also for immunohistochemical analysis to detect P53 and P21WAF-1 protein expression and distribution.RESULTS: In histopathological study, ameliorated intestinal structures were observed at 2, 6, and 12 h after reperfusion in A group compared to R group. The apoptotic rates were (41.17±3.49)%, (42.83±5.23)%,and (53.33±6.92)% at 2, 6, and 12 h after reperfusion,respectively in A group, which were apparently lower than those in R group at their matched time points(50.67±6.95)%, (54.17±7.86)%, and (64.33±6.47)%,respectively, (P<0.05)). The protein contents of P53and P21WAF-1 were both significantly decreased in A group compared to R group (P<0.05) at 2-12 h after reperfusion, while the mRNA levels of P53 and P21WAF-1in A group were obviously lower than those in R group at6-12 h after reperfusion (P<0.05).CONCLUSION: P53 and P21WAF-1 protein accumulations are associated with intestinal barrier injury induced by I-R insult, while intravenous aFGF can alleviate apoptosis of rat intestinal cells by inhibiting P53