Sequential observations show upregulation of TGF-beta1 at the early phase of chronic small bowel rejection in rats.

Although TGF-beta1 is related to chronic rejection in various solid organs, its role remains controversial in the setting of small bowel transplantation. The aim of this study is to investigate the distinct role of TGF-beta1 and its receptors in the setting of chronic small bowel rejection. Sequential protocol biopsies were performed every 2 weeks from week 2 till week 8 after transplantation and recipients were sacrificed at week 16 as the end point. Gene expression was evaluated by SYBR Green I real-time polymerase chain reaction and protein was determined by immunohistochemistry. The gene expressions of TGF-beta1 and Type I receptor were upregulated and attained statistical significance at 4, 6 and 8 weeks in allografts. Dynamic expressions of TGF-beta1 and Type I receptor mRNA shown by sequential protocol biopsies support the view that TGF-beta1 signaling is involved in the pathogenesis of chronic small bowel rejection, especially at the early phase.