CASP3 and necrotizing enterocolitis: As is shown in Figures 2(a), 2(b), 2(c), and 2(d) and Figures 3(a), 3(b), 3(c), and 3(d), with TUNEL, IHC, and immunofluorescence staining, more positive cells with apoptotic characteristics and more positive expression of Caspase 3 and higher fluorescence intensity of BAX, whereas less Bcl-2 fluorescence intensity was found of intestine tissues in NEC rats in relative to control group (P < 0.05 or P < 0.01).