Apoptosis of retinal capillary cells and expression of p53 in rats with spontaneous hypertension after ischemic reperfusion injury

Abstract

Objective To investigate the effect of apoptosis-related gene p53 on the apoptosis of retinal capillary cells in rats with spontaneously hypertensive (SHR) after ischemic reperfusion injury. Methods A total of 60 SHR rats were randomly divided into sham group (SHR-SH) and retinal ischemie reperfusion group (SHR-RIR), which were subdivided into 5 subgroups according to the time after RIR: 2, 6, 24, and 72 hours and 7 days, with 6 rats in each subgroup. Another 60 Wistar-Kyoto (WKY) rats were divided into the same groups as the SHR rats as the control. The RIR model was set up. The apoptosis of retinal capillary cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) methods and the expression of p53 was determined by streptavidin-perosidase (SP) immunohistochemistry. Results The apoptosis rate of retinal capillary cells in the 5 SHR-RIR groups was (8.64±0.56)%, (14.92±0.99)%, (24.72±2.98)%, (16.53±1.80)%, and (7.12±1.10)%,respectively. The expression of p53 in SHR-RIR groups increased at the 2nd hour after RIR, reached the peak at the 24th hour, kept the high level at the 72nd hour, and remained a little at the 7th day, which was significantly different from which in the SHR-SH groups (P<0. 01). The expression of p53 were higher in SHR-IR groups than that in the WKY-RIR groups (P<0. 01). Conclusions p53 may play a part in RIR injury by inducing or promoting apoptosis. The apoptosis of retinal capillary cells after RIR is more severe under the hypertension, and reaches the peak at the 24 hour after RIR. Key words: Reperfusion Injury; Apoptosis; Genes, p53; Rats, Inbred Dahl