Metabolic disorders can induce psychiatric comorbidities. Both brain and neuronal composition imbalances reportedly induce an anxiety-like phenotype. We hypothesized that alterations of localized brain areas and cholecystokinin (CCK) and parvalbumin (PV) expression could induce anxiety-like behavior in type 2 diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats. Twenty-week-old OLETF and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats were used. The areas of corticolimbic regions were smaller in OLETF rats. The densities of CCK positive neurons in the lateral and basolateral amygdala, hippocampal cornu ammonis area 2, and prelimbic cortex were higher in OLETF rats. The densities of PV positive neurons were comparable between OLETF and LETO rats. Locomotion in the center zone in the open field test was lower in OLETF rats. These results suggest that imbalances of specific brain region areas and neuronal compositions in emotion-related areas increase the prevalence of anxiety-like behaviors in OLETF rats.

Octanoyl, dodecanoyl and hexadecanoyl ascorbates were synthesized by the condensation of ascorbic acid and the corresponding fatty acids in acetone using an immobilized lipase from Candida antarctica. The oxidation process of methyl linoleate (ML) as an oil droplet in the ML/W emulsion with ascorbic acid or acyl ascorbate was measured at 40°C, and their antioxidative properties were examined. Hydrophilic proxidant, AAPH, or lipophilic proxidant, AMVN, was added to the water or oil phase to investigate the properties, and the kinetic parameters for the oxidation expressed by the Weibull equation were evaluated. It was suggested that most of the ascorbic acid molecules in the emulsion would be present in the water phase due to its high hydrophilicity and suppress the AAPH-induced oxidation on the interface between the water and oil phases. Dodecanoyl and hexadecanoyl ascorbates would be dissolved in the oil phase and contribute to the suppression of the oxidation in the oil phase rather than on the interface. Octanoyl ascorbate with a HLB number of 11.8 would be in both phases. Regardless of the presence and type of the ascorbate, the rate constant, k, of the Weibull equation decreased as the pH of the water phase increased.

Mild hyperbaric treatment prevents type 2 diabetes progression due to increased oxygen concentration and blood flow in skeletal muscle. However, it remains unknown whether this treatment is effective during all stages of type 2 diabetes. This study aimed to investigate the influences of hyperbaric treatment at 1.3 atmospheres absolute (ATA) on hemodynamic response in various stages of type 2 diabetes. Otsuka Long-Evans Tokushima fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) rats were used as models of type 2 diabetes and healthy controls, respectively. Glucose levels were significantly higher in OLETF rats than in LETO rats at all ages. Glucose intolerance gradually increased with age in OLETF rats. Insulin levels in OLETF rats were significantly higher at 20-week-old, however, were significantly lower at 60-week-old than in LETO rats. Oxy-Hb, total Hb, and StO 2 in skeletal muscle were increased during hyperbaric treatment in both rats. The hemodynamic changes were significantly higher in OLETF rats than LETO rats, and those changes were also pronounced at 8-week-old compared with other age in OLETF rats. These results suggest that hyperbaric treatment at 1.3 ATA acts on pathophysiological factors and the efficacy could be found only in the early stage of type 2 diabetes.

Hyperbaric treatment improves hyperglycemia and hyperinsulinemia in type 2 diabetes associated with obesity. However, its mode of action is unknown. The purpose of the present study was to investigate the influences of regular hyperbaric treatment with normal air at 1.3 atmospheres absolute (ATA) on glucose tolerance in type 2 diabetes with obesity. The focus was directed on inflammatory cytokines in the adipose tissue and skeletal muscle. Otsuka Long-Evans Tokushima Fatty (OLETF) rats were used as models of type 2 diabetes with obesity and Long-Evans Tokushima Otsuka (LETO) rats served as healthy controls. The rats were randomly assigned to untreated or hyperbaric treatment groups exposed to 1.3 ATA for 8 h d−1 and 5 d wk−1 for 16 wks. Glucose levels were significantly higher in the diabetic than in the healthy control rats. Nevertheless, glucose levels at 30 and 60 min after glucose administration were significantly lower in the diabetic rats treated with 1.3 ATA than in the untreated diabetic rats. Insulin levels at fasting and 120 min after glucose administration were significantly lower in the diabetic rats treated with 1.3 ATA than in the untreated diabetic rats. Hyperbaric treatment also increased interleukin-10 (IL-10) expression in the skeletal muscle and decreased tumor necrosis factor α (TNFα) expression in adipose tissue. These results suggested that TNFα downregulation and IL-10 upregulation in diabetic rats subjected to hyperbaric treatment participate in the crosstalk between the adipose and skeletal muscle tissues and improve glucose intolerance.

Sex difference in susceptibility to oral infection with Corynebacterium (C.) kutscheri was experimentally studied in ICR mice. Immature (4-week-old) and adult (14-week-old) mice were inoculated with two infecting doses of C. kutscheri, and necropsied for bacteriological and serological survey 4 weeks after the bacterial infection. No macroscopic lesions at necropsy were demonstrated, except for one adult male given 10(9) bacteria. In immature mice, C. Kutscheri isolated from the oral cavity and cecum with FNC agar, were recovered in only 40.0% of female mice but in 90.0% of male mice given 10(6) bacteria (p < 0.05), and in only 55.6% of female mice but in 80.0% male mice given 10(8) bacteria. In adult mice given 10(9) bacteria, the organism were recovered in only 45.5% of female mice but in 90.9% of male mice (p < 0.05), furthermore, the mean number of organisms in the cecum of male mice harboring the organism was significantly higher than that in females (p < 0.01). Castration caused an increase in host resistance in adult male mice. These results indicated that ICR male mice were more susceptible than females, in terms of bacterial colonization in the cecum and the oral cavity, to oral infection with C. kutscheri.