Morphological changes of pancreatic ducts in Otsuka Long-evans Tokushima Fatty rats

Progression of pancreatitis prior to diabetes onset in WBN/Kob-Lepr(fa) rats

We established the WBN/Kob-Lepr(fa) rat as a new congenic strain for the fa allele of the leptin receptor gene (Lepr). Homozygous (fa/fa) WBN/Kob-Lepr(fa) rats provide a model of non-insulin-dependent diabetes, although its onset is secondary to pancreatitis. In the present study, we compared histopathological observations of pancreatitis in each genotype of this rat, to examine its suitability as a model of pancreatitis. The histopathological findings of the pancreatitis revealed intense changes dependent on age, such as hemorrhage or hemosiderin deposition. The pancreatitis in homozygous (fa/fa) WBN/Kob-Lepr(fa) rats were more severe than those of WBN/Kob rats.

Protective effect of Hachimi-jio-gan against the development of pancreatic fibrosis and oxidative damage in Otsuka Long-Evans Tokushima Fatty rats

In our previous study, the polyherbal drug Hachimi-jio-gan was reported to possess a protective effect against the progression of diabetic nephropathy by attenuating glucose toxicity and renal damage with a type 2 diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Based on these findings, this study was undertaken to reveal the effect of Hachimi-jio-gan on pancreatic damage focusing on fibrosis and oxidative stress in type 2 diabetes. OLETF rats were orally administered Hachimi-jio-gan for 32 weeks, and we assessed the changes in the serum glucose level every 8 weeks, as well as those of body weight, and food and water consumption every 4 weeks. In addition, pancreatic wet weight, insulin content, and Western blot analyses of transforming growth factor-beta(1), fibronectin, and nuclear factor-kappaB-related inflammatory enzymes, such as inducible nitric oxide synthesis and cyclooxygenase-2, were also performed in the pancreas. As a consequence, long-term treatment with Hachimi-jio-gan had a hypoglycemic effect, reducing pancreatic atrophy and fibrosis, and ameliorating the oxidative status. Therefore, this may provide evidence that Hachimi-jio-gan is a therapeutic target for preventing the development of pancreatic damage concomitant with hyperglycemia in type 2 diabetes.