Suppressive Effect of Herbal Medicine Saikokeishito on Acinar Cell Apoptosis in Rat Spontaneous Chronic Pancreatitis

Abstract

Background/Aims: Chronic pancreatitis is characterized by acinar destruction and fibrosis. We previously reported that apoptosis is involved in acinar destruction in chronic pancreatitis in the WBN/Kob rat. This study aimed to elucidate the antiapoptotic effect of Saikokeishito (TJ-10). Methods: Fourweek-old male WBN/Kob rats were fed a special pellet diet (MB-3) with or without TJ-10 (80 mg/100 g body weight) for 20 weeks. Pancreas was histopathologically examined every 4 weeks, and the expression of apoptosis-related factors such as Fas and Fas ligand (FasL) mRNA and protein was analyzed with RT-PCR, in situ hybridization and immunohistochemistry. Apoptosis was detected with a TUNEL method. Results: In untreated WBN/Kob rats, chronic pancreatitis developed at 12 weeks and progressed with marked acinar cell destruction at 16 weeks. The expression of Fas and FasL peaked at 12 and 20 weeks. An apoptotic index in acinar cells correlated to the expression of Fas and FasL mRNA. However, in the TJ-10-treated rats, the rate of pancreatic acinar cell destruction, the apoptotic index at 12–20 weeks, and the expression of Fas and FasL at 12 and 20 weeks decreased significantly compared to those in untreated rats. Conclusion: These results suggest that TJ-10 has a therapeutic effect on chronic pancreatitis by the suppression of acinar cell apoptosis via the Fas/FasL system.