TSOD Mice Research Articles

Oral Intake of Linseed Oil Inhibits Skin Barrier Dysfunction in Obese Mice.

Obesity is not only a risk factor for lifestyle-related diseases but also causes skin barrier dysfunction, which leads to a reduced quality of life due to dryness, itching, and scratching, and thus requires appropriate treatment. However, there are no studies on this issue. Therefore, this study aimed to examine whether oral intake of linseed oil is effective for skin barrier function in obesity and to confirm how the effect is demonstrated. TSOD mice received either sterile distilled water (Control group) or linseed oil (Omega group), containing a high level of omega-3 fatty acids, including α-linolenic acid, orally for eight weeks. Mice were then irradiated with ultraviolet B (UVB) and three days later, transepidermal water loss (TEWL), which is the primary outcome of skin barrier function, was measured and gross skin appearance was observed. Hematoxylin and eosin (HE) staining and Ki-67 immunostaining were performed on skin samples. mRNA expression levels of the inflammatory markers Tnfα, Cox2, Mcp1, and Hmox1 were measured by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). We also performed fatty acid analysis of skin and erythrocytes by gas chromatography.Statistical analysis was performed using unpaired Student's t-test and Pearson's correlation analysis. Compared with the Control group, the Omega group exhibited lower TEWL values and little skin erythema. Histological analysis revealed thinner epidermis and fewer Ki-67 positive cells. Additionally, in the Omega group, mRNA levels of four inflammation-related genes were lower, α-linolenic acid levels in both skin and erythrocytes were higher, and a lower n-6/n-3 ratio was observed.And α-linolenic acid levels in the skin were negatively correlated with the expression levels of inflammation-related genes. Oral intake of linseed oil was found to inhibit skin barrier dysfunction in obesity. This effect was mediated by α-linolenic acid, a major component of linseed oil with anti-inflammatory properties, which was taken up by erythrocytes and supplied to the skin. Therefore, oral intake of linseed oil is expected to be a useful therapeutic method forskin barrier dysfunction in obesity.

Impacts of liver macrophages, gut microbiota, and bile acid metabolism on the differences in iHFC diet-induced MASH progression between TSNO and TSOD mice.

Tsumura-Suzuki non-obese (TSNO) mice exhibit a severe form of metabolic dysfunction-associated steatohepatitis (MASH) with advanced liver fibrosis upon feeding a high-fat/cholesterol/cholate-based (iHFC) diet. Another ddY strain, Tsumura-Suzuki diabetes obese (TSOD) mice, are impaired in the progression of iHFC diet-induced MASH. To elucidate the underlying mechanisms contributing to the differences in MASH progression between TSNO and TSOD mice. We analyzed differences in the immune system, gut microbiota, and bile acid metabolism in TSNO and TSOD mice fed with a normal diet (ND) or an iHFC diet. TSOD mice had more anti-inflammatory macrophages in the liver than TSNO mice under ND feeding, and were impaired in the iHFC diet-induced accumulation of fibrosis-associated macrophages and formation of histological hepatic crown-like structures in the liver. The gut microbiota of TSOD mice also exhibited a distinct community composition with lower diversity and higher abundance of Akkermansia muciniphila compared with that in TSNO mice. Finally, TSOD mice had lower levels of bile acids linked to intestinal barrier disruption under iHFC feeding. The dynamics of liver macrophage subsets, and the compositions of the gut microbiota and bile acids at steady state and post-onset of MASH, had major impacts on MASH development.

Effect of inactivated Bifidobacterium longum intake on obese diabetes model mice (TSOD).

Obesity and diabetes have been increasing at an alarming rate worldwide. Studies have shown the futility of chemical drugs in the treatment of obesity and diabetes. Bifidobacterium longum (BL), a common member of the gut microbiota throughout the human lifespan, has been widely reported to play a role in host health and disease. Here, we evaluated the effects of inactivated cells of BL (IBL) on obesity and blood glucose levels in TSOD mice by administering IBL orally for 5weeks. The treated mice showed a significant decrease of body weight gain, adipose tissue mass and blood glucose levels, as well as a significant reduction in blood glucose during an oral glucose tolerance test. The treatment also resulted in reduced levels of cholesterol, triglycerides, and NEFA. Moreover, serum and urine analysis showed low creatinine levels in IBL-treated mice. These data demonstrate that IBL may have the potential to prevent obesity and diabetes.

Oral administration of an herbal medicine to prevent progressive hearing loss in a mouse model of diabetes

ObjectiveTsumura Suzuki Obese Diabetes (TSOD) mice exhibit early age-associated hearing loss. Histopathological analysis of these mice shows narrowing of capillaries in the stria vascularis and chronic reduction of blood flow in the cochlea. In this study, we investigated the effect of oral administration of a herbal medicine or calorie restriction on hearing in TSOD mice. MethodsTSOD mice were divided into 4 groups: CR (calorie restriction), BF and DS (treated with the herbal medicines, Bofutsushosan and Daisaikoto, respectively), and the control group. Body weight, blood glucose levels, and auditory brainstem responses (ABRs) were measured. The cochleae were excised and evaluated histopathologically. ResultsBlood glucose levels were suppressed in the CR, BF, and DS groups. In addition, the elevation of ABR thresholds was inhibited in the CR, BF, and DS groups. Cochlear blood vessels remained wide in the three treatment groups compared with the control group. These results suggested that the administration of these herbal medicines improved glucose tolerance and yielded results similar to those on calorie restriction. ConclusionOral administration of 2 herbal medicines can prevent hearing function disorder in a model mouse of diabetes. The results may clarify the possibility of clinical application.

MTOR Activation in Liver Tumors Is Associated with Metabolic Syndrome and Non-Alcoholic Steatohepatitis in Both Mouse Models and Humans.

Non-alcoholic steatohepatitis (NASH) can cause liver fibrosis and cirrhosis, with final progression to hepatocellular carcinoma (HCC) in some cases. Various factors have been suggested to be involved in the development of NASH. Considering the many possible contributing factors, we postulated that mechanisms of progression from NASH to HCC could differ depending on the risk factors. In the present study, we applied two mouse models of NASH–HCC and performed histopathological and proteome analyses of mouse liver tumors. Furthermore, to compare the mechanisms of NASH–HCC progression in mice and humans, we investigated HCCs in humans with a background of metabolic syndrome and NASH, as well as HCCs associated with hepatitis virus infection by immunohistochemistry. It was demonstrated that upstream regulators associated with the mammalian target of rapamycin (mTOR) pathway were altered in liver tumors of mice with metabolic syndrome characteristics (TSOD mice) using proteome analysis. Immunohistochemical analysis showed that mTOR was characteristically phosphorylated in liver tumors of TSOD mice and HCCs from metabolic syndrome cases in humans. These results indicated that the mTOR pathway is characteristically activated in liver tumors with metabolic syndrome and NASH, unlike liver tumors with other etiologies.

Salacia reticulata has therapeutic effects on obesity.

Salacia reticulata Wight (S. reticulata) is a herbal medicine used for treatment of early diabetes in Ayurvedic medicine. In previous reports, the extract of S. reticulata showed preventive effects on obesity and various metabolic disorders and a suppressive effect on differentiation in premature adipocytes. The aim of this research was to elucidate the therapeutic efficacy of the extract of S. reticulata on obesity and various metabolic disorders in 12-week-old TSOD mice with obesity and metabolic disorders and in mature 3T3-L1 adipocytes. In TSOD mice, S. reticulata therapy produced a reduction in body weight and mesenteric fat accumulation, an improvement in abnormal glucose metabolism, and an increase in adiponectin level in plasma. In addition, the mRNA expressions of hormone-sensitive lipase (HSL) and adiponectin were increased in mesenteric fat. In in vitro experiments, S. reticulata therapy produced suppression of intracellular triacylglycerol accumulation and enhancement of glycerol release into the medium in mature 3T3-L1 cells. The mRNA expressions of lipogenesis factor (peroxisome proliferator-activated receptor γ, lipoprotein lipase, CD36, and fatty acid binding protein 4) were down-regulated, while the expressions of lipolysis factor (adipose tissue triacylglycerol lipase and HSL) and adiponectin were up-regulated. Moreover, the extract of S. reticulata enhanced the expression of total AMP-activated protein kinase α (AMPKα) and phosphorylated AMPKα in mature adipocytes. These findings demonstrate that the extract of S. reticulata has therapeutic effects on obesity and metabolic disorders by enhancing lipogenesis genes and suppressing lipolysis genes through the activation of AMPKα in adipocytes.

Suppression of adipocyte hypertrophy by polymethoxyflavonoids isolated from Kaempferia parviflora

We previously demonstrated that ethyl acetate extracts of Kaempferia parviflora Wall. Ex Baker (KPE) improve insulin resistance in TSOD mice and showed that its components induce differentiation and adipogenesis in 3T3-L1 preadipocytes. The present study was undertaken to examine whether KPE and its isolated twelve components suppress further lipid accumulation in 3T3-L1 mature adipocytes. KPE reduced intracellular triglycerides in mature adipocytes, as did two of its components, 3,5,7,3′,4′-pentamethoxyflavone and 5,7,4′-trimethoxyflavone. Shrinkage of lipid droplets in mature adipocytes was observed, and mRNA expression levels of adipose tissue triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) were up-regulated by these two polymethoxyflavonoids (PMFs). Furthermore, the protein expression level of ATGL and the release level of glycerol into the cell culture medium increased. In contrast, the peroxisome proliferator-activated receptor γ (PPARγ) agonist, troglitazone, did not decrease intracellular triglycerides in mature adipocytes, and the mRNA expression level of PPARγ was not up-regulated in mature adipocytes treated with the two active PMFs. Therefore, suppression of lipid accumulation in mature adipocytes is unlikely to be enhanced by transcriptional activation of PPARγ. These results suggest that KPE and its active components enhance lipolysis in mature adipocytes by activation of ATGL and HSL independent of PPARγ transcription, thus preventing adipocyte hypertrophy. On the other hand, the full hydroxylated flavonoid quercetin did not show the suppressive effects of lipid accumulation in mature adipocyte in the same conditions. Consequently, methoxy groups in the flavones are important for the activity.

Pentraxin 3 Production in the Adipose Tissue and the Skeletal Muscle in Diabetic-Obese Mice

Inflammation has been shown to promote obesity-induced insulin resistance. Although pentraxin (PTX) 3 is known as an antiinflammatory factor, the effect of PTX3 on insulin sensitivity has not yet been elucidated. The aim of this study is to investigate a part of the role of PTX3 on insulin sensitivity. The authors studied the PTX3 and glucose transport protein expression levels in epididymal adipose tissue and soleus muscles of male diabetic-obese [Tsumura Suzuki obese-diabetic (TsoD)] and lean control mice. The levels of PTX3 in both skeletal muscle and adipose tissue were significantly lower in TSOD mice than in controls, and there was a significant positive correlation between them. They observed a significant positive correlation between PTX3 and glucose transport protein 4 levels in skeletal muscle. This study suggests that PTX3 may play a part of role as promoting insulin sensitivity of skeletal muscle in TSOD mice.

Puerariae flos alleviates metabolic diseases in Western diet-loaded, spontaneously obese type 2 diabetic model mice

Puerariae flos extract (PFE) has been reported to have many effects, including preventing the development of hangovers, liver protective effects, and an estrogenic effect. In addition, some papers reported that PFE is effective against metabolic diseases, with hypolipidemic and hypoglycemic effects. However, the mechanism underlying such effects remains unclear. For the purpose of clarifying the effect of PFE on metabolic diseases related to the accumulation of visceral fat and to determine the mechanism of such action, TSOD mice, a multifactorial genetic disease animal model that spontaneously develops various metabolic diseases such as obesity and type 2 diabetes, were given a Western diet (WTD) as an environmental factor to prepare a disease model (TSOD-WTD). When TSOD mice were loaded with WTD, it was confirmed that metabolic diseases such as obesity and abnormal glucose/lipid metabolism are aggravated. In contrast, PFE treatment to TSOD-WTD mice was shown to suppress body weight gain and visceral fat accumulation, alleviated the abnormal glucose tolerance and hyperinsulinemia, as well as causing an increase in blood adiponectin. Furthermore, the suppression of liver enlargement was observed in PFE-treated mice, with suppression of fatty degeneration and anti-inflammatory effect. In addition, to clarify the mechanism of the hyperlipidemia-alleviating effects in the liver, we investigated the effect of PFE on the expression of genes involved in cholesterol homeostasis. PFE was associated with a significant increase in gene expression for cholesterol synthesis rate-limiting enzyme HMG-CoA reductase, cholesterol catabolization enzyme Cyp7A1, bile salt export pump adenosine triphosphate-binding cassette transporter B11, and low-density lipoprotein receptor involved in cholesterol uptake. The above results suggest that PFE acts to alleviate the effects of various metabolic diseases based on the accumulation of visceral adipose tissue, including obesity, diabetes, and hyperlipidemia, with the promotion of catabolization/excretion of cholesterol in the liver being a key mechanism of action.

Preventive effect of Terminalia bellirica on obesity and metabolic disorders in spontaneously obese type 2 diabetic model mice

Visceral obesity induces insulin resistance and is recognized as an important risk factor for metabolic syndrome (MS). Therefore, inhibition of lipid absorption from the intestine is regarded as an effective way of preventing MS. Terminalia bellirica is extensively used in Ayurvedic medicine in India and neighboring countries, and the fruit of this plant has been reported to have hypoglycemic and hypolipidemic effects. In this study, we investigated the preventive effect of a hot water extract of T. bellirica fruit (TB) on obesity and various metabolic disorders, and explored its molecular mechanisms and active ingredients. TB treatment had a preventive effect on obesity, insulin resistance, and hyperlipidemia in spontaneously obese type 2 diabetic TSOD mice. To clarify the molecular mechanisms of TB in preventing obesity, we investigated the inhibitory effect on lipid absorption. TB suppressed absorption of triacylglycerol in an olive oil loading test (in vivo) and showed a strong inhibitory effect on pancreatic lipase activity (in vitro). Furthermore, a search for the active ingredients in TB revealed that gallic acid is the component primarily responsible for the inhibition of pancreatic lipase activity. Thus, our findings indicate that TB could be useful in preventing MS. The mechanisms probably involve suppression of the absorption of meal-derived lipids mediated by gallic acid.

Preventive effect of Kaempferia parviflora ethyl acetate extract and its major components polymethoxyflavonoid on metabolic diseases

Previously, we reported that rhizome powder of Kaempferia parviflora Wall. Ex. Baker prevented obesity and a range of metabolic diseases. In this study, to clarify which molecular mechanisms and active ingredients of K. parviflora have an anti-obesity effect, we investigated the effect of ethyl acetate extract of K. parviflora (KPE) on TSOD mice, a spontaneously obese Type II diabetes model, and on pancreatic lipase. In the TSOD groups, KPE showed a suppressive effect on body weight increase and visceral fat accumulation and also showed preventive effects on symptoms related to insulin resistance, hypertension and fatty liver. In addition, KPE also suppressed body weight increase and food intake in TSNO mice groups, which served as reference animals, at an early stage of administration. Searching for the ingredients in KPE revealed that KPE contains at least 12 kinds of polymethoxyflavonoid (PMF). Furthermore, KPE and its component PMFs showed an inhibitory effect on pancreatic lipase. The above results suggest that KPE has a preventive effect on obesity and various metabolic diseases. The mechanisms of action probably involve inhibition of pancreatic lipase by the PMFs in KPE.

Preventive Effects of Salacia reticulata on Obesity and Metabolic Disorders in TSOD Mice

The extracts of Salacia reticulata (Salacia extract), a plant that has been used for the treatment of early diabetes, rheumatism and gonorrhea in Ayurveda, have been shown to have an anti-obesity effect and suppress hyperglycemia. In this study, the effects of Salacia extract on various symptoms of metabolic disorder were investigated and compared using these TSOD mice and non-obese TSNO mice. Body weight, food intake, plasma biochemistry, visceral and subcutaneous fat (X-ray and CT), glucose tolerance, blood pressure and pain tolerance were measured, and histopathological examination of the liver was carried out. A significant dose-dependent decline in the gain in body weight, accumulation of visceral and subcutaneous fat and an improvement of abnormal glucose tolerance, hypertension and peripheral neuropathy were noticed in TSOD mice. In addition, hepatocellular swelling, fatty degeneration of hepatocytes, inflammatory cell infiltration and single-cell necrosis were observed on histopathological examination of the liver in TSOD mice. Salacia extract markedly improved these symptoms upon treatment. Based on the above results, it is concluded that Salacia extract has remarkable potential to prevent obesity and associated metabolic disorders including the development of metabolic syndrome.

Preventive Effect of Geniposide on Metabolic Disease Status in Spontaneously Obese Type 2 Diabetic Mice and Free Fatty Acid-Treated HepG2 Cells

Accumulation of visceral fat induces various symptoms of metabolic syndrome such as insulin resistance and abnormal glucose/lipid metabolism and eventually leads to the onset of ischemic cerebrovascular diseases. Geniposide, which is iridoid glycoside from the fruit of Gardenia jasminoides ELLIS, is recognized as being useful against hyperlipidemia and fatty liver. In order to clarify the effect of geniposide on metabolic disease-based visceral fat accumulation and the relevant molecular mechanism, experiments were performed in spontaneously obese Type 2 diabetic TSOD mice and the free fatty acid-treated HepG2 cells. In the TSOD mice, geniposide showed suppression of body weight and visceral fat accumulation, alleviation of abnormal lipid metabolism and suppression of intrahepatic lipid accumulation. In addition, geniposide alleviated abnormal glucose tolerance and hyperinsulinemia, suggesting that geniposide has an insulin resistance-alleviating effect. Next, in order to investigate the direct effect of geniposide on the liver, the effect on the free fatty acid-treated HepG2 fatty liver model was investigated using genipin, which is the aglycone portion of geniposide. Genipin suppressed the intracellular lipid accumulation caused by the free fatty acid treatment and also significantly increased the intracellular expression of a fatty acid oxidation-related gene (peroxisomal proliferator-activated receptor: PPARα). From these results, it was confirmed that geniposide has an anti-obesity effect, an insulin resistance-alleviating effect and an abnormal lipid metabolism-alleviating effect, and the metabolite genipin shows a direct effect on the liver, inducing expression of a lipid metabolism-related gene as one of its molecular mechanisms.

Prevention of Adiposity by the Oral Administration of ?-Cryptoxanthin

β-Cryptoxanthin (β-CRX) is a carotenoid found in human blood. It is specifically rich in Satsuma mandarin (Citrus unshiu Marc.) but very little in other fruits or vegetables. Several reports indicate the health promoting benefits of β-CRX. As we had reported visceral fat reduction on mildly obese male by the oral administration of β-CRX, a detailed mechanism has not been identified. To identify the mechanism, obese model mouse, TSOD was used in the present study. Oral administration of β-CRX repressed body weight, abdominal adipose tissue weight, and serum lipid concentrations on TSOD mice. The outstanding observation is the significant repression of adipocyte hypertrophy. DNA microarray analysis strongly indicates that the oral administration of β-CRX represses the inflammatory cytokine secretion and improves the lipid metabolism and the energy consumption. It also suggests these effects are partly mediated by PPAR-α, not only lipid metabolism and adipocyte differentiation control but possibly internal circadian clock modulation.

Feeding of aged garlic extract improves glucose intolerance and fatty liver in spontaneous diabetic mice

Garlic, a common herb, is widely used as medicinal plant, but its usefulness in the treatment of diabetes has not been established. Aged garlic extract (AGE) that contains unique compounds such as S‐allyl cysteine were produced as a result of aging processes. We studied the effect of AGE using two models of spontaneous diabetic animals, TSOD and ddY‐H, developed by Dr. W. Suzuki (Tsumura & Co., Japan) and Dr. T. Maeda (Univ. of Shizuoka, Japan), respectively. These mice showed various phenotypes of type 2 diabetes, including high blood glucose, glucose intolerance, high circulating level of insulin and fatty liver. TSOD mice fed diet containing 4% (w/w) AGE for 6 months, had a lower level of blood glucose compared to control, although their body weight was still high and AGE treatment had no adverse effects. In addition, glucose intolerance was ameliorated in AGE‐fed TSOD mice. Furthermore, triglyceride accumulation in the liver of these mice was reduced compared to that in control. Moreover, the level of SREBP1c, PPAR‐gamma and GLUT2 mRNAs was lower in the liver of AGE‐fed TSOD mice. Similar results were obtained by experiments using another diabetic model, ddY‐H mice. In conclusion, our data indicated that AGE prevents occurrence of glucose intolerance and fatty liver in diabetic mice, suggesting that AGE is useful for the prevention and treatment of type 2 diabetes.

Altered expression of CYP in TSOD mice: a model of type 2 diabetes and obesity

Altered expression of CYP in TSOD mice: a model of type 2 diabetes and obesity

Diabetic Complications in a New Animal Model (TSOD mouse) of Spontaneous NIDDM with Obesity

The TSOD mouse has been established as an inbred strain with spontaneous development of diabetes mellitus as the first clinical signs of diabetes. Polydipsia and polyuria are observed at about 2 months old only in male mice, after which hyperglycemia and hyperinsulinemia are detected. Following these symptoms obesity gradually develops until about 12 months old. In histopathological examination of the pancreas, severe hypertrophy of pancreatic islets was observed due to proliferation and swelling of B cells. In the kidney, thickening of the basement membrane in glomeruli and an increase of the mesangial area were observed at 18 months old. Motor neuropathy in TSOD mice began to appear at 14 months old and most male mice at 17 months old showed weakness of front and hind paws caused by neuron degeneration in the peripheral nerve. In sensory neuropathy, the threshold in the tail pressure test decreased significantly at 12 months old. Light microscopic and electron microscopic examination of sciatic nerves showed a decrease in the density of nerve fibers by the endoneural fibrosis and loss of these fibers. Degenerative changes of myelinated fibers, separation of myelin sheaths with intralamellar edema and remyelination were frequently observed. In the severely affected nerve fibers, the lamellar structure was completely destroyed and macrophages migrated around the myelin sheath or invaded the intramyelin space. Considering these findings similar to non-insulin dependent diabetes mellitus (NIDDM) in humans, the TSOD mouse should be a useful model for the pathogenic study of diabetic complications, especially of peripheral neuropathy.

A new mouse model of spontaneous diabetes derived from ddY strain.

By the selective breeding of obese male mice of the ddY strain and using indices of the heavy body weight and appearance of urinary glucose, we established two inbred strains in 1992: one with obesity and urinary glucose (Tsumura, Suzuki, Obese Diabetes: TSOD) and the other without them (Tsumura, Suzuki, Non Obesity: TSNO). The male TSOD mice constantly showed signs of obesity and urinary glucose with increases in food and water intake, body weight and some fat weight. The body mass index (BMI) clearly showed moderate obesity. Increases in the levels of diabetic blood parameters (glucose, insulin and lipids) were also found in males, in which the levels of blood glucose and insulin were high to the ages past the growth peak. In the histological studies, pancreatic islets of the TSOD males were found hypertrophic without any signs of insulitis or fibrous formation. Among these diabetic characteristics, some of which were similar to the reported models of non-insulin-dependent diabetes mellitus (NIDDM), the stable appearances of the hyperglycemia, the hyperinsulinemia and the hypertrophy of pancreatic islets to the ages past the growth peak were the prominent features. In these respect the TSOD mouse may be a useful model for researching the mechanisms of human diabetes and its complications.