ABSTRACT
To compare the pancreatic proteomics and autophagy between Rehmanniae Radix-and Rehmanniae Radix Praeparata-treated mice with type 2 diabetes mellitus(T2DM). The T2DM mouse model was established by high-fat diet coupled with streptozotocin(STZ, intraperitoneal injection, 100 mg·kg~(-1), once a day for three consecutive days). The mice were then randomly assigned into a control group, low-(5 g·kg~(-1)) and high-dose(15 g·kg~(-1)) Rehmanniae Radix groups, low-(150 mg·kg~(-1)) and high-dose(300 mg·kg~(-1)) catalpol groups, low-(5 g·kg~(-1)) and high-dose(15 g·kg~(-1)) Rehmanniae Radix Praeparata groups, low-(150 mg·kg~(-1)) and high-dose(300 mg·kg~(-1)) 5-hydroxymethyl furfuraldehyde(5-HMF) groups, and a metformin(250 mg·kg~(-1)) group. In addition, a normal group was also set and each group included 8 mice. The pancreas was collected after four weeks of administration and proteomics tools were employed to study the effects of Rehmanniae Radix and Rehmanniae Radix Praeparata on protein expression in the pancreas of T2DM mice. The expression levels of proteins involved in autophagy, inflammation, and oxidative stress response in the pancreatic tissues of T2DM mice were determined by western blotting, immunohistochemical assay, and transmission electron microscopy. The results showed that the differential proteins between the model group and Rehmanniae Radix/Rehmanniae Radix Prae-parata group were enriched in 7 KEGG pathways, such as autophagy-animal, which indicated that the 7 pathways may be associated with T2DM. Compared with the control group, drug administration significantly up-regulated the expression levels of beclin1 and phosphorylated mammalian target of rapamycin(p-mTOR)/mTOR and down-regulated those of the inflammation indicators, Toll-like receptor-4(TLR4) and Nod-like receptor protein 3(NLRP3), in the pancreas of T2DM mice, and Rehmanniae Radix showed better performance. In addition, the expression levels of inducible nitric oxide synthase(iNOS), nuclear factor erythroid 2-related factor 2(Nrf2), and heine oxygenase-1(HO-1) in the pancreas of T2DM mice were down-regulated after drug administration, and Rehmanniae Radix Praeparata demonstrated better performance. The results indicate that both Rehmanniae Radix and Rehmanniae Radix Praeparata can alleviate the inflammatory symptoms, reduce oxidative stress response, and increase the autophagy level in the pancreas of T2DM mice, while they exert the effect on different autophagy pathways.