Salivary gland dysfunction is a common complication of diabetes. Decreased saliva production and changes in saliva composition may cause oral diseases. Reactive oxygen species (ROS) generation in the salivary glands results in the loss of acinar cells and decreased saliva secretion. Glucagon-like peptide 1 (GLP-1) is the incretin hormone that regulates blood glucose level and can suppress ROS production and inflammation through its antioxidant effects. Dipeptidyl peptidase-4 (DPP-4) is an enzyme that breaks down GLP-1. In this study, we evaluated the pathological role of DPP-4 and GLP-1 on salivary gland dysfunction in type 2 diabetic db/db mice. We observed reduced salivary secretion and histopathological alteration of salivary glands in the db/db mice. The increased DPP-4 and decreased GLP-1 levels in the salivary glands were also detected in the db/db mice. Furthermore, the db/db mice had increased apoptosis and oxidative injury in salivary glands. There was an accumulation of advanced glycation end products and mucus in the salivary glands of the db/db mice. In conclusion, these results showed the possible involvement of DPP-4 and GLP-1, leading to increased ROS-induced apoptosis in diabetes-related salivary gland dysfunction. DPP-4 and GLP-1 may be a pharmacological target for patients with diabetes-related salivary gland dysfunction.

The objective of this study was to determine the anti-diabetic effect of the water extract of Neolentinus lepideus in a diabetic mouse model. Seven-week-old C57BL/KsJ-db/db mice were fed either a control diet (CD) or diet supplemented with 1% or 5% of N. lepideus water extract (NLWE1 or NLWE5) for 10 weeks. Oral administration of NLWE significantly decreased the body weight gain compared to that of CD-fed group. Mice in the NLWE group had significantly lower levels of fasting serum glucose, fatty acids, and low-density lipoprotein cholesterol compared to those in the control group. These effects were accompanied by reduced fatty liver and improved glucose tolerance in the NLWE group. Taken together, these results suggest that N. lepideus might have potential as a dietary supplement to control diabetes.

This study investigated the antidiabetic effect of amaranth grain ethanol extract (AEE) in a diabetic animal model, db/db mouse. The mice were divided into 4 groups: normal control mice (C57BL/6J), diabetic mice (C57BL/6J db/db), diabetic mice fed a lower concentration of AEE (0.3 mg/kg), and diabetic mice fed a higher concentration of AEE (0.5 mg/kg). After 10 weeks of treatment, body weights, blood insulin levels and blood glucose levels of each group were compared. At the end of treatment, the results showed that both AEE supplemented groups had lower body weights than those in the diabetic groups although higher than those in the normal groups. Moreover, in both AEE supplemented groups, serum insulin levels were higher and blood glucose levels were lower than those in the diabetic groups although both values were higher than those in the normal groups. The results of this study suggest that AEE can alleviate many of the common symptoms of diabetes in diabetic mice and, therefore, has potential as a therapeutic supplement for normalization of blood glucose and insulin levels in humans.

Anti-diabetic activities of cultured mycelia from Ganoderma applanatum are being evaluated in this study. The OGTT and 4-weeks of repeated oral efficacy tests are conducted in mice at the doses of 0 (vehicle treatment), 25, 75 and 225 ㎎/㎏/day, respectively. In human study, the test article was administered orally every day for 8-week at a dose of 1,500 ㎎/㎏, tid and placebo group. The blood glucose levels (BGL) at 0.5 hour after treatment are significant decreased in all treatment groups of OGTT test. In the 4-week test, BGL of 75 and 225 ㎎/㎏/day group is continuously decreased during all treatment periods and the BGL of 25 ㎎/㎏/day group show decreasing trends at the final week, the pancreas weight of all treatment groups are being increased, and the Langerhans-islet numbers were increased at all treatment groups with a dose-response manner. There are no test article-related abnormal signs and the fasted blood glucose (FBG), postprandial blood glucose (PPG) and HbA1c are decreased significantly after 8-week treatments. These results that the cultured mycelia from Ganoderma applanatum could decrease BGL by protecting the degeneration of Langerhans islets.

Brucellosis is an important bacterial zoonosis in humans and domestic animals. Brucella spp. are taken up, and survive within non-professional and professional phagocytes. In common belief, diabetes mellitus increases susceptibility to pathogenic infection. In this study, Brucella (B.) abortus was inoculated into a diabetic animal model, db/db mice, in order to show the course of brucellosis in diabetic state. The liver proliferation, bacterial burden of the liver, level of cytokines in serum and macrophage migration into liver, were investigated at 14 days post-infection. In comparison with the uninfected control mice, the results revealed that the weight of the liver of infected db/db mice was higher but with lower bacterial load in this organ. The level of MCP-1 mRNA expression in the liver was lower, the levels of IL-12p70, IL-10, TNF-α and IFN-γ in serum was significantly higher and the macrophages migration was significantly lower in infected mice than in the control group. In conclusion, this present study suggested that MCP-1 suppression by B. abortus infection may inhibit the macrophages migration, and consequently may induce to abrogate the bacterial survival in db/db mouse liver. Furthermore, the increased inflammatory cytokines may contribute to inhibition of B. abortus proliferation in diabetic mice.

The goal of this study was to examine the ameliorative effects of black ginseng(BG) in male obese diabetic C57BLKS/ J-db/db mice. Ten-week-old male db/db mice were administrated 300 ㎎/㎏ of F-BG daily for 6 weeks, The db/db mice where corresponded to the normal group and db/db mice which were the diabetic positive group were not provided BG treatment. The supressive effects of treatment were examined on serum lipids levels, which included total cholesterol, triglyceride, LDL-cholesterol and nonesterified fatty acid. Also, weight changes and the relative weight of liver and kidney, organ pathological investigation were measured. The effects of treatment were assessed by comparing the results of the db/db mice that received BG for 6 weeks with that of the diabetic positive group. Significant differences in several biological parameters such as HDL level(p<0.05), TG level(p<0.05) and NEFA level(p<0.05) were observed for the BG group. BG treatment increased the HDL level and decreased the NEFA level, which could ameliorate hyperlipidemia or blood circulation.

The aim of the present study was to evaluate the beneficial effects of Eriobotryae Folium on diabetic improvement through oxidative stress and inflammation in the liver of type 2 diabetic db/db mice. Eriobotryae Folium extract (100 or 200 mg/kg body weight, p.o) was administrated everyday for 3 weeks. And then, its effect was assessed on comparison with vehicle-treated db/db and non-diabetic m/m mice. Serum glucose and hepatic tissue biochemical factors and protein expression related with oxidative stress and inflammation such as reactive oxygen species (ROS) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase were measured. As a result, the administration of Eriobotryae Folium decreased body and liver weight, food intake in vehicle-treated db/db. Also, serum glucose was lowered by Eriobotryae Folium treatment. Eriobotryae Folium administration decreased oxidative stress through the down-regulation of ROS and NADPH oxidase subunit proteins, NOX-4 and p47 phox .Moreover,theincreaseofinflammatoryproteinssuchasinduciblenitricoxidesynthase(iNO S),cyclooxygenase-2(COX-2),tumornecrosisfactoralpha(TNF-α), interleukin-6 (IL-6) on vehicle-treated db/db were significantly decreased through down-regulation nuclear factor-kappa B (NF-κB) and activator pretoein-1 (AP-1) via reduction of oxidative stress. Therefore, hepatic functional parameters such as alanine aminotransferase, aspartate aminotransferase significantly decreased. In conclusion, Eriobotryae Folium extract could have hepato-protective effect through down-regulation of abnormal NADPH oxidase subunit and the oxidative stress in type 2 diabetic db/db mice.