Effects of gamma irradiation on BCL2 and TPR53BP2 expression in the porcine ciliary body.

BACKGROUND

When dissection of porcine eyes from a living body results in the cessation of aqueous humor production and blood flow, programmed cell death regulated by TPR53BP2 and BCL2 genes may occur in the pigmented epithelium (PE) and non-pigmented epithelium (NPE) of the ciliary body. Blood products are subjected to gamma irradiation in order to prevent cellular damage resulting from transfusion-associated graft-versus-host disease. We investigated whether gamma irradiation influenced BCL2 or TPR53BP2 genes as well as the morphology of the porcine ciliary body.

METHODS

We irradiated the anterior segments of porcine eyes by using (60)Co gamma-rays (20 Gy). To study BCL2 and TPR53BP2 expression, the irradiated specimens were fixed in formalin and embedded in paraffin and then incubated with mouse monoclonal anti-human BCL2 or TPR53BP2 antibody.

RESULTS

Following dissection, an imbalance in homeostasis began with positive BCL2 and TPR53BP2 expression in the edematous ciliary processes, and resulted in atrophy of the NPE. Increased BCL2 and TPR53BP2 expression were evident just after gamma irradiation. Decreased TPR53BP2 expression occurred after 8 h of incubation, and thereby suppressed apoptosis in the NPE; hence, the structure of the ciliary body that was incubated for 8 h after gamma irradiation was well preserved.

CONCLUSIONS

Irradiation renders the ciliary body in enucleated porcine eyes less vulnerable to apoptosis, and thereby exerts a profound preservative effect.