Sub-acute oral exposure to lowest observed adverse effect level of nivalenol exacerbates atopic dermatitis in mice via direct activation of mitogen-activated protein kinase signal in antigen-presenting cells.

This study investigated the immunotoxic effects of the mycotoxin nivalenol (NIV) using antigen-presenting cells and a mouse model of atopic dermatitis (AD). In vitro experiments were conducted using a mouse macrophage cell line (RAW 264.7) and mouse dendritic cell line (DC 2.4). After cells were exposed to NIV (0.19-5 µmol) for 24 h, the production of pro-inflammatory cytokines (IL-1ß, IL-6, and TNFα) was quantified. To further investigate the inflammatory cytokine production pathway, the possible involvement of mitogen-activated protein kinase (MAPK) pathways, such as ERK1/2, p-38, and JNK, in NIV exposure was analyzed using MAPK inhibitors and phosphorylation analyses. In addition, the pro-inflammatory effects of oral exposure to NIV at low concentrations (1 or 5 ppm) were evaluated in an NC/Nga mouse model of hapten-induced AD. In vitro experiments demonstrated that exposure to NIV significantly enhanced the production of TNFα. In addition, it also directly induced the phosphorylation of MAPK, indicated by the inhibition of TNFα production following pretreatment with MAPK inhibitors. Oral exposure to NIV significantly exacerbated the symptoms of AD, including a significant increase in helper T cells and IgE-produced B cells in auricular lymph nodes and secretion of pro-inflammatory cytokines, such as IL-4, IL-5, and IL-13, compared with the vehicle control group. Our findings indicate that exposure to NIV directly enhanced the phosphorylation of ERK1/2, p-38, and JNK, resulting in a significant increase in TNFα production in antigen-presenting cells, which is closely related to the development of atopic dermatitis.

Chronic oral exposure to low-concentration fumonisin B2 significantly exacerbates the inflammatory responses of allergies in mice via inhibition of IL-10 release by regulatory T cells in gut-associated lymphoid tissue.

Contamination with fumonisins produced by Fusarium spp. is rapidly growing in both developing and developed countries. The purpose of this study was to determine whether oral exposure to fumonisin contributed to the development of allergic diseases. We initially examined the immunotoxic potential of short-term, oral administration of fumonisin B1 (FB1, 1 mg/kg) and fumonisin B2 (FB2, 1 mg/kg), both naturally occurring fumonisins, using a BALB/c mouse model of allergic contact dermatitis and Dermatophagoides farina-induced asthma. Using an NC/nga mouse model of atopic dermatitis (AD), we evaluated the adverse effects of subchronic oral exposure to low concentrations of FB2 (2 or 200 µg/kg). Finally, we explored the influence of FB2 on regulatory T cell proliferation and function in mesenteric lymph nodes after 1-week oral exposure to FB2 in BALB/c mice. Oral exposure to FB2 markedly exacerbated the symptoms of allergy, including skin thickness, histological evaluation, immunocyte proliferation, and proinflammatory cytokine production, although no change was observed following exposure to FB1. Furthermore, oral exposure to low concentrations of FB2 considerably exacerbated the AD scores, skin thickness, transepidermal water loss, histological features, and proinflammatory cytokine production. The aggravated allergic symptoms induced by oral exposure to FB2 could be attributed to the direct inhibition of IL-10 production by regulatory T cells in mesenteric lymph nodes. Our findings indicate that the recommended maximum fumonisin level should be reconsidered based on the potential for allergy development.

Effects of low concentrations of ozone gas exposure on percutaneous oxygen saturation and inflammatory responses in a mouse model of Dermatophagoides farinae-induced asthma.

Ozone gas is widely used in hospitals as well as homes to control COVID-19 infection owing to its cost-effectiveness. Safety standard value and the tolerable value of ozone gas are set at 0.05 ppm and 0.1 ppm, respectively, in developed countries; however, this value was principally determined for healthy individuals, and the risks associated with ozone gas inhalation in patients with pulmonary diseases remains unknown. Recently, we demonstrated that 0.1 ppm ozone gas exposure significantly aggravates the symptoms of acute lung injury in mice. In the present study, we further examined the influence of ≤ 0.1 ppm ozone gas exposure on percutaneous oxygen saturation (SpO2) and pro-inflammatory responses in a mouse model of asthma. Female BALB/c mice were subjected to repetitive intranasal sensitization of Dermatophagoides farinae to generate a mouse model of asthma. Inhalation exposure of ozone gas (0.1, 0.03, 0.01 ppm), generated using an ultraviolet lamp, was performed for five consecutive days immediately before the final sacrifice. There were no abnormal findings in control mice exposed to 0.1 ppm ozone; however, 0.1 ppm ozone exposure significantly reduced the SpO2 level in asthmatic mice. Histological evaluation and gene expression analysis revealed that pro-inflammatory cytokine levels were significantly increased in mice exposed to 0.1 ppm ozone, indicating that 0.1 ppm ozone exposure affects the development of asthma symptoms. Notably, 0.03 and 0.01 ppm ozone exposure did not have any effects even in asthmatic mice. Our findings indicate that the tolerable level of ozone gas should be adjusted for individuals based on a history of respiratory disorders.

Oral exposure to citrinin significantly exacerbates the pathophysiology of a mouse model of imiquimod-induced psoriasis via direct activation of dendritic cell.

Citrinin, a mycotoxin produced by Penicillium citrinum and Penicillium verrucosum, mainly contaminates cereals. The aim of study was to investigate the novel immunoreactive effect of citrinin using a mouse model of psoriasis. A mouse model of psoriasis was generated by topical application of 5% imiquimod in female BALB/c mice. Standard rodent diet and rice samples with 3 ppm of citrinin were mixed to obtain a final citrinin concentration of 0.3 ppm, and a citrinin-contaminated diet was fed to mice daily. Skin thickness, scratching behavior, and trans epidermal water loss (TEWL) were monitored continuously during the imiquimod application. Immediately after the final imiquimod application, ear skin and auricular lymph node (LN) were sampled for further analysis. Only a slight increase was observed in skin thickness in the citrinin exposure group; however, citrinin exposure significantly exacerbated hyperkeratinization and inflammatory cell infiltration in histological evaluation. TEWL, which is representative of cutaneous barrier function, was significantly increased by citrinin exposure. In terms of immune function, the number of immune cells in LN (T cells and dendritic cells) and gene expression of interleukin (IL)-17 in skin tissue were significantly increased by citrinin exposure. Direct interaction of dendritic cells (DCs) in citrinin-induced psoriasis development was further examined by proinflammatory cytokine determination in THP-1 cells and murine bone marrow derived DCs. IL-6 and/or tumor necrosis factor α were significantly increased by citrinin exposure. Taken together, our results imply that oral exposure to citrinin exacerbates the symptoms of a mouse model of psoriasis via direct activation of DCs.

Mouse Models with SGLT2 Mutations: Toward Understanding the Role of SGLT2 beyond Glucose Reabsorption.

The sodium-glucose cotransporter 2 (SGLT2) mainly carries out glucose reabsorption in the kidney. Familial renal glycosuria, which is a mutation of SGLT2, is known to excrete glucose in the urine, but blood glucose levels are almost normal. Therefore, SGLT2 inhibitors are attracting attention as a new therapeutic drug for diabetes, which is increasing worldwide. In fact, SGLT2 inhibitors not only suppress hyperglycemia but also reduce renal, heart, and cardiovascular diseases. However, whether long-term SGLT2 inhibition is completely harmless requires further investigation. In this context, mice with mutations in SGLT2 have been generated and detailed studies are being conducted, e.g., the SGLT2-/- mouse, Sweet Pee mouse, Jimbee mouse, and SAMP10-ΔSglt2 mouse. Biological changes associated with SGLT2 mutations have been reported in these model mice, suggesting that SGLT2 is not only responsible for sugar reabsorption but is also related to other functions, such as bone metabolism, longevity, and cognitive functions. In this review, we present the characteristics of these mutant mice. Moreover, because the relationship between diabetes and Alzheimer's disease has been discussed, we examined the relationship between changes in glucose homeostasis and the amyloid precursor protein in SGLT2 mutant mice.

Fructose prevents the development of hyperglycaemia in WBN/Kob diabetic fatty rats via maintaining high insulin levels.

Fructose is considered to negatively affect type 2 diabetes mellitus (T2DM); however, there are contradictory reports. The present study aimed to elucidate the effects of fructose-rich diet (FRD) on glucose metabolism of Wistar Bonn Kobori (WBN/Kob) fatty diabetic (WBKDF) rats, a spontaneous T2DM model, and Wistar rats. Wistar Bonn Kobori fatty diabetic and Wistar rats were fed either FRD or standard diet (STD) for 4 weeks. The food intake, body weight, plasma glucose and insulin were measured weekly. After the 4-week challenge, rats were subjected to an intravenous glucose tolerance test (IVGTT). The liver and pancreas were used for histological analysis. The 4-week challenge of FRD in Wistar rats did not cause hyperglycaemia, but increased insulin resistance (Homeostatic Model Assessment for Insulin Resistance [HOMA-IR]). Feeding WBKDF rats with a FRD accelerated obesity, but prevented the onset of severe hyperglycaemia via maintaining high plasma insulin levels. Homeostatic Model Assessment for Insulin Resistance in WBKDF rats was not changed by FRD feeding. Intravenous glucose tolerance test revealed that FRD feeding in Wistar rats did not affect glucose tolerance, but slightly increased the plasma insulin level. In contrast, FRD feeding in WBKDF rats significantly reduced the glucose tolerance, but insulin response was not improved. Fructose-rich diet feeding did not alter the ß cell area in Wistar rats, but significantly increased it in WBKDF rats. In conclusion, FRD caused insulin resistance in Wistar rats, suggesting that fructose overconsumption is a risk factor for T2DM, whereas FRD inhibited severe hyperglycaemia by maintaining high insulin levels in WBKDF rats. Fructose may be a beneficial sugar for T2DM patients with severe obesity-induced insulin resistance.

Acute and subacute oral administration of mycotoxin deoxynivalenol exacerbates the pro-inflammatory and pro-pruritic responses in a mouse model of allergic dermatitis.

Deoxynivalenol (DON) contamination in food is a public health concern; however, the effect of DON exposure on immune disorders including allergies remains unclear. The aim of this study is to elucidate the effect of oral exposure to DON on pro-inflammatory and pro-pruritic responses in a mouse model of allergic dermatitis, which was generated by topical application of toluene-2,4-diisocyanate (TDI), a hapten that induces type-2 helper T cells. To evaluate acute exposure to DON, the mice were orally administered vehicle alone, 0.1 mg/kg DON, or 0.3 mg/kg DON 48, 24, and 1 h before the final challenge with TDI. To study subacute exposure, the mice were fed DON-contaminated rodent diet (0.3 ppm) during the experimental period. After the itch behavior and ear-swelling response were monitored, the serum, auricular lymph node, and skin tissue were collected for analyzing immunocyte differentiation, cytokine determination, and histological changes. Acute oral administration of DON significantly enhanced pro-inflammatory responses including ear-swelling response, immunocyte infiltration, and cytokine productions. Histological evaluation supported the occurrence of pro-inflammatory responses. In contrast, acute DON exposure only slightly increased itch behavior. Subacute oral exposure to DON significantly up-regulated the inflammatory responses, but showed almost no effect on pruritic response. In vitro evaluation in dendritic cells and keratinocytes indicated that DON pre-exposure induced a dose-dependent significant increase in cytokine production. Our results imply that both acute and subacute exposures to DON are associated with pro-inflammatory responses in cutaneous allergy.

Estrogen receptor α activation aggravates imiquimod-induced psoriasis-like dermatitis in mice by enhancing dendritic cell interleukin-23 secretion.

Our recent study has reported that estrogen receptors (ERs) are involved in several types of allergy development. This study aims to investigate the possible relationship between ER activation and development of imiquimod-induced psoriasis-like dermatitis. A mouse model of imiquimod-induced psoriasis-like dermatitis was generated by 5 days of topical application of 5% of imiquimod cream on the back of the ear and the shaved back skin of male BALB/c mice. From the second day of applying 5% imiquimod cream, either ERα selective agonist (propylpyrazoletriol [PPT] 2.5 mg/kg) or ERß selective agonist (diarylpropionitrile, DPN; 2.5 mg/kg) was administered orally for four consecutive days. Immediately after the final imiquimod cream application, scratching behavior was video monitored for 2 hours. The ear-swelling response was determined by comparing ear thickness before and after the final application of imiquimod cream. Twenty-four hours after the final imiquimod application, back skin tissue and auricular lymph nodes were isolated under isoflurane anesthesia. Oral administration of PPT significantly induced itch behavior and proinflammatory responses, including the levels of interleukin (IL)-17 and IL-22, whereas DPN treatment did not influence either pruritic or proinflammatory responses. In addition, IL-23 contribution by dendritic cells was identified using ER agonists on pretreated lipopolysaccharide (LPS)-stimulated murine bone marrow derived dendritic cells (BMDCs). PPT also significantly enhanced IL-23 secretion by LPS-stimulated BMDCs. Our findings indicate that the activation of ERα, but not ERß, is directly associated with inflammatory and pruritic responses in a mouse model of the imiquimod-induced psoriasis by enhancing the secretion of IL-23 by dendritic cells.

Mutation in Sodium-Glucose Cotransporter 2 Results in Down-Regulation of Amyloid Beta (A4) Precursor-Like Protein 1 in Young Age, Which May Lead to Poor Memory Retention in Old Age.

Senescence-accelerated mouse prone 10 (SAMP10) exhibits cerebral atrophy and depression-like behavior. A line of SAMP10 with spontaneous mutation in the Slc5a2 gene encoding the sodium-glucose cotransporter (SGLT) 2 was named SAMP10/TaSlc-Slc5a2slc (SAMP10-ΔSglt2) and was identified as a renal diabetes model. In contrast, a line of SAMP10 with no mutation in SGLT2 (SAMP10/TaIdrSlc, SAMP10(+)) was recently established under a specific pathogen-free condition. Here, we examined the mutation effect in SGLT2 on brain function and longevity. No differences were found in the survival curve, depression-like behavior, and age-related brain atrophy between SAMP10-ΔSglt2 and SAMP10(+). However, memory retention was lower in SAMP10-ΔSglt2 mice than SAMP10(+). Amyloid beta (A4) precursor-like protein 1 (Aplp1) expression was significantly lower in the hippocampus of SAMP10-ΔSGLT2 than in SAMP10(+) at 2 months of age, but was similar at 12 months of age. CaM kinase-like vesicle association (Camkv) expression was remarkably lower in SAMP10(+). These genes have been reported to be involved in dendrite function. Amyloid precursor proteins have been reported to involve in maintaining homeostasis of glucose and insulin. These results suggest that mutation in SGLT2 results in down-regulation of Aplp1 in young age, which can lead to poor memory retention in old age.

Effects of high-sodium intake on systemic blood pressure and vascular responses in spontaneously diabetic WBN/Kob-Leprfa/fa rats.

The prevalence of type 2 diabetes mellitus (T2DM) and hypertension has markedly increased worldwide. The purpose of the present study was to examine the effects of a high-salt intake on the systolic blood pressure (SBP) and vascular responses in WBN/Kob-Leprfa/fa (WBKDF) rats, a new spontaneous animal model of T2DM. Male WBKDF rats and age-matched Wistar rats at 6 weeks of age were each divided into two groups and fed either a normal-sodium (NS, 0.26%) diet or high-sodium (HS, 8%) diet for 14 weeks: (i) Wistar rats on NS diet (Wistar-NS); (ii) Wistar rats on HS diet (Wistar-HS); (iii) WBKDF rats on NS diet (WBKDF-NS); (iv) WBKDF rats on HS diets (WBKDF-HS). Neither WBKDF-NS nor Wistar-NS rats showed significant changes in SBP throughout the experiment, but both WBKDF-HS and Wistar-HS exhibited significant elevation of SBP, which was more prominent (P<.01) in WBKDF-HS than in Wistar-HS. Phenylephrine-induced contractions of isolated thoracic aortic rings were significantly (P<.01) enhanced in WBKDF-HS and Wistar-HS compared with the respective strain of rats on the NS diet. In contrast, acetylcholine- and nitroprusside-induced relaxation were significantly (P<.01) diminished in both WBKDF-HS and Wistar-HS, and these HS diet-induced changes were more profound (P<.01) in WBKDF rats than in Wistar rats. Significantly (P<.05) higher plasma concentrations of 8-iso-prostaglandin F2α and sodium ions were observed in WBKDF-HS than in Wistar-HS. The current study demonstrated that WBKDF-HS rats developed salt-sensitive hypertension associated with vascular dysfunction. The WBKDF rat may be a useful model for investigating the etiology of hypertension with T2DM.

Therapeutic potential of ozone water treatment in alleviating atopic dermatitis symptoms in mouse models: Exploring its bactericidal and direct anti-inflammatory properties.

Currently, ozone water is utilized for antibacterial and antiviral purposes without any reported safety concerns. Therefore, ozone water may have clinical applications in treating staphylococcal-specific cutaneous diseases, such as atopic dermatitis (AD) and pyoderma. This study aimed to verify the bactericidal effects of ozone water at different concentrations (3 and 11 mg/L) against staphylococcal species in vitro, as well as evaluate the anti-inflammatory effects of ozone water in a mouse model of AD and pyoderma. Initially, the bactericidal properties of several concentrations of ozone water were confirmed with Staphylococcus aureus and methicillin-resistant S. pseudintermedius. Both 3 and 11 mg/L of ozone water exhibited a significant bactericidal effect against staphylococci at less than 100 times dilution. We next examined the cellular cytotoxicity and cytokine production (Interleukin (IL)-6 and IL-8) induced by S. pseudintermedius pre-treated with ozone water, and our findings indicated that cytotoxicity and cytokine production induced by staphylococci were significantly inhibited after ozone water pre-treatment. In vivo experiments showed that ozone water-pre-treated S. pseudintermedius significantly inhibited the development of pyoderma in mice; however, limited effects were observed in a therapeutic setting. Interestingly, ozone water at concentrations of 3 and 11 mg/L exhibits dual bactericidal and anti-inflammatory effects in mice with AD. This observation was corroborated by the significant inhibition of cytokine production in interferon-γ/tumor necrosis factor-stimulated human epidermal keratinocyte cells exposed to ozone in vitro. These findings indicate that administering ozone can be a novel therapeutic approach for managing allergic skin diseases, such as AD.

Topical treatment with mastic (resin from Pistacia lentiscus) elicits anti-inflammatory and anti-pruritic responses by modulating keratinocyte activation in a mouse model of allergic dermatitis.

BACKGROUND: As the number of patients with skin allergies, including atopic dermatitis, has increased rapidly, therapeutic options such as anti-IL-31 antibody and Janus kinase inhibitor have been developed recently. However, many concerns remain regarding the adverse effects and cost of these drugs; therefore, development of supplements that could support the effect of therapeutic agents is always required. PURPOSE: The aim of this study was to develop preventive and supportive options for skin allergies by focusing on a natural product called "Mastic". METHODS: Initially, the anti-inflammatory and anti-pruritic responses of 3% and 30% Mastic topical treatment were investigated in a mouse model of allergic contact dermatitis, generated by topical application of toluene-2,4-diisocyanate (TDI), a hapten that induces type 2 helper T cells. After itch behaviour and ear-swelling response were monitored, serum, auricular lymph nodes, and skin tissues were collected to analyse immunocyte differentiation, cytokine determination, and histological changes. RESULTS: Our findings indicated that topical treatment with mastic significantly ameliorated ear swelling, itch behaviour, immunocyte infiltration, and cytokine production. Histological evaluation confirmed the occurrence of anti-inflammatory responses. The anti-inflammatory and anti-pruritic effects of topical treatment with mastic (3% and 5%) were further confirmed in a mouse model of atopic dermatitis which was generated by topical application of TDI in NC/Nga mice. Thickness of the back skin, AD score, transepidermal water loss (TEWL), and itch behaviour were measured weekly, and immunocyte differentiation, cytokine determination, and histological changes were also analysed. Mastic treatment significantly attenuated the skin thickness, AD score, TEWL, and itch behaviour. Corroborated reduction was observed in the numbers of T cells and IgE-B cells, as well as in pro-inflammatory cytokine production. The reproducibility of the effects of mastic was confirmed with 1% mastic ointment in a setting similar to the AD mouse model. In vitro evaluation of keratinocytes indicated that mastic pre-exposure induced a significant dose-dependent decrease in cytokine production. CONCLUSION: Our findings thus demonstrate that topical treatment with mastic significantly ameliorate inflammatory and pruritic responses in a mouse model of allergic dermatitis.

Acute and Subacute Oral Toxicity of Deoxynivalenol Exposure in a Dermatophagoides farinae-Induced Murine Asthma Model.

Previously, researchers have demonstrated that mycotoxin deoxynivalenol (DON) significantly enhances immunocyte activation. However, the interaction between DON exposure and immune disorders remains unclear. In this study, we aimed to investigate whether acute and subacute oral exposure to DON exacerbates the development of respiratory allergy using a mite allergen (Dermatophagoides farina, Derf)-induced mouse model of asthma. The direct relationship between DON exposure and asthma development was examined following acute oral DON administration (0, 0.1, or 0.3 mg/kg body weight), immediately before the final mite allergen challenge. Simultaneously, the influence of subacute oral exposure via low dose DON contaminated wheat (0.33 ppm) was evaluated using the same settings. To detect the proinflammatory effects of DON exposure, we examined the total and Derf-specific serum IgE levels, histology, number of immunocytes, and cytokine and chemokine secretion. Acute oral DON significantly enhanced the inflammatory responses, including cellular infiltration into bronchoalveolar lavage fluid, infiltration of immunocytes and cytokine production in local lymph nodes, and cytokine levels in lung tissues. Corresponding proinflammatory responses were observed in a mouse group exposed to subacute oral DON. In vivo results were validated by in vitro experiments using the human bronchial epithelial (BEAS-2B) and human eosinophilic leukemia (EOL-1) cell lines. Following exposure to DON, the secretion of interleukin (IL)-1ß, IL-6, IL-8, and/or tumor necrosis factor-α in BEAS-2B cells, as well as EoL-1 cells, increased significantly. Our findings indicate that DON exposure is significantly involved in the proinflammatory response observed in respiratory allergy.

Effects of liraglutide on metabolic syndrome in WBN/Kob diabetic fatty rats supplemented with a high-fat diet.

BACKGROUND: Liraglutide, a GLP-1 receptor agonist, has recently been used to treat metabolic syndrome (MS) because of its anti-diabetic and anti-obesity effects. We have previously shown that Wistar Bonn Kobori diabetic and fatty (WBN/Kob-Lepr fa , WBKDF) rats fed a high-fat diet (HFD) developed MS including marked obesity, hyperglycemia, and dyslipidemia. To obtain further information on WBKDF-HFD rats as a severe MS model, we performed a pharmacological investigation into the anti-MS effects of liraglutide in this model. METHODS: Seven-week-old male WBKDF-HFD rats were allocated to three groups (N = 8 in each group): a vehicle group, a low-dose liraglutide group, and a high-dose liraglutide group. They received subcutaneous injections of either saline or liraglutide at doses of 75 or 300 µg/kg body weight once daily for 4 weeks. RESULTS: Results showed that liraglutide treatment reduced body weight gain and food intake in a dose-dependent manner. The marked hyperglycemia and the glucose tolerance were also significantly ameliorated in the liraglutide-treated groups. Moreover, liraglutide also reduced the plasma triglyceride concentration and liver fat accumulation. CONCLUSIONS: The present study demonstrated that liraglutide could significantly alleviate MS in WBKDF-HFD rats, and the reaction to liraglutide is similar to human patients with MS. WBKDF-HFD rats are therefore considered to be a useful model for research on severe human MS.

High-Salt Intake Ameliorates Hyperglycemia and Insulin Resistance in WBN/Kob-Leprfa/fa Rats: A New Model of Type 2 Diabetes Mellitus.

High-salt intake is a major risk factor for developing hypertension in type 2 diabetes mellitus, but its effects on glucose homeostasis are controversial. We previously found that high-salt intake induces severe hypertension in WBN/Kob diabetic fatty (WBKDF) rats. In the present study, we examined the effects of a high-salt intake on glucose homeostasis in WBKDF rats. Male WBKDF rats and age-matched Wistar rats at 6 weeks of age were each divided into two groups and fed either a normal-sodium (NS, 0.26%) diet or high-sodium (HS, 8%) diet for 7 weeks. Systolic blood pressure and urine volume were increased in WBKDF-HS and Wistar-HS. Body weight gain and food consumption were comparable between NS and HS in both strains. Plasma and urine glucose levels were significantly increased in WBKDF-NS but not in WBKDF-HS. HOMA-IR in WBKDF-HS was significantly lower compared with that in WBKDF-NS. The high plasma adiponectin level in WBKDF-NS compared with that in Wistar-NS was further enhanced in WBKDF-HS. Glycogen deposits and fat droplets in the livers of WBKDF-HS were reduced compared with those of WBKDF-NS. The present study demonstrated that HS intake ameliorated hyperglycemia and insulin resistance in WBKDF rats, which may be due to increased plasma levels of adiponectin.

Effects of high-fat diet and fructose-rich diet on obesity, dyslipidemia and hyperglycemia in the WBN/Kob-Leprfa rat, a new model of type 2 diabetes mellitus.

Obesity and type 2 diabetes mellitus (T2DM) are occurring at epidemic-like rates, and these epidemics appear to have emerged largely from changes in daily diet. In the present study, we compared effects of high-fat diet (HFD) and fructose-rich diet (FRD) in WBN/Kob-Leprfa (WBKDF) rats that spontaneously develop obesity, dyslipidemia and T2DM. After a 4-week feeding of each diet, WBKDF-HFD and WBKDF-FRD rats exhibited aggravated obesity and dyslipidemia compared with WBKDF rats fed standard diet (STD). In contrast, hyperglycemia developed in WBKDF-STD rats was significantly inhibited in WBKDF-FRD rats, but not in WBKDF-HFD rats. The present study demonstrated that the 4-week feeding of HFD and FRD caused diet-induced obesity with a distinct phenotype in the glucose metabolism in WBKDF rats.

Mammary adenoma with sebaceous differentiation in a dog.

The current report describes a complex canine mammary adenoma with a rare histological feature characterized by sebaceous differentiation of tumor cells. A 13-year-old, mixed-breed, intact female dog had mammary tumors on the right mammary chain. Histologically, one of the masses was composed of bilayered ductal structures with luminal epithelial cells together with basaloid or myoepithelial cell components. Within the tumor, there were a number of lobules and nests of large foamy cells associated with basaloid reserve-like cells similar to sebaceous gland. Squamous metaplasia was also seen within the tumor. Immunohistochemical staining indicated that the tumor cells with sebaceous differentiation were positive for cytokeratin (CK)14 and that the associated basaloid reserve-like cells were positive for p63. In contrast, other luminal epithelial tumor cells were positive for CK18 and CK19, but not for CK14 and p63. The myoepithelial cells were positive for α-smooth muscle actin and p63. The expression of p63 in both sebaceous basaloid reserve-like cells and myoepithelial cells, and their structural continuity within the tumor tissue, suggested a common origin of these 2 components.