BB Rats Research Articles

Arylphthalide Delays Diabetic Retinopathy via Immunomodulating the Early Inflammatory Response in an Animal Model of Type 1 Diabetes Mellitus.

Diabetic retinopathy (DR) is one of the most prevalent secondary complications associated with diabetes. Specifically, Type 1 Diabetes Mellitus (T1D) has an immune component that may determine the evolution of DR by compromising the immune response of the retina, which is mediated by microglia. In the early stages of DR, the permeabilization of the blood-retinal barrier allows immune cells from the peripheral system to interact with the retinal immune system. The use of new bioactive molecules, such as 3-(2,4-dihydroxyphenyl)phthalide (M9), with powerful anti-inflammatory activity, might represent an advance in the treatment of diseases like DR by targeting the immune systems responsible for its onset and progression. Our research aimed to investigate the molecular mechanisms involved in the interaction of specific cells of the innate immune system during the progression of DR and the reduction in inflammatory processes contributing to the pathology. In vitro studies were conducted exposing Bv.2 microglial and Raw264.7 macrophage cells to proinflammatory stimuli for 24 h, in the presence or absence of M9. Ex vivo and in vivo approaches were performed in BB rats, an animal model for T1D. Retinal explants from BB rats were cultured with M9. Retinas from BB rats treated for 15 days with M9 via intraperitoneal injection were analyzed to determine survival, cellular signaling, and inflammatory markers using qPCR, Western blot, or immunofluorescence approaches. Retinal structure images were acquired via Spectral-Domain-Optical Coherence Tomography (SD-OCT). Our results show that the treatment with M9 significantly reduces inflammatory processes in in vitro, ex vivo, and in vivo models of DR. M9 works by inhibiting the proinflammatory responses during DR progression mainly affecting immune cell responses. It also induces an anti-inflammatory response, primarily mediated by microglial cells, leading to the synthesis of Arginase-1 and Hemeoxygenase-1(HO-1). Ultimately, in vivo administration of M9 preserves the retinal integrity from the degeneration associated with DR progression. Our findings demonstrate a specific interaction between both retinal and systemic immune cells in the progression of DR, with a differential response to treatment, mainly driven by microglia in the anti-inflammatory action. In vivo treatment with M9 induces a switch in immune cell phenotypes and functions that contributes to delaying the DR progression, positioning microglial cells as a new and specific therapeutic target in DR.

A Diet Producing a Low Diabetes Incidence Modifies Immune Abnormalities in Diabetes-Prone BB Rats

The effect of feeding a diet that produces a high or low incidence of diabetes on immune abnormalities proposed to contribute to the pathogenesis of autoimmune-mediated diabetes was investigated. Diabetes-prone (BBdp) and nondiabetes-prone (BBn) BB rats (21 d) were fed for 21 d a nonpurified (high incidence) or purified (low diabetes incidence) diet. Compared with BBn, immune cells from spleen and mesenteric lymph nodes of BBdp rats demonstrated higher rates of metabolite production from glucose and glutamine, higher splenic cytotoxicity (lysis of 51Cr-labeled YAC-1 cells) and lower mitogen responses (3H thymidine uptake). Bypassing the membrane, using the mitogen phorbol myristate acetate + lonomycin, improved the BBdp mitogen response, suggesting a membrane defect. Immune cells from BBdp rats fed the purified, compared with the nonpurified, diet had lower rates of glutamine (spleen) and glucose (lymph nodes) metabolism and lower splenic cytotoxic activity. Although diet altered the proportion of T and B cells in lymph nodes of BBdp rats, it did not correct the abnormal lymphocyte distribution or effect mitogen responses. Feeding the purified, compared with nonpurified, diet to BBn rats altered energy metabolism by lymph node cells and resulted in lower splenic cytotoxic activity. Reduced splenic natural killer cell activity and decreased immune cell metabolism are unlikely the mechanism for the preventative effect of feeding a purified diet to BBdp rats but are indicative of reduced immune activity.

Unravelling the Inflammatory Processes in the Early Stages of Diabetic Nephropathy and the Potential Effect of (Ss)-DS-ONJ.

Inflammatory processes play a central role in the pathogenesis of diabetic nephropathy (DN) in the early stages of the disease. The authors demonstrate that the glycolipid mimetic (Ss)-DS-ONJ is able to abolish inflammation via the induction of autophagy flux and provokes the inhibition of inflammasome complex in ex vivo and in vitro models, using adult kidney explants from BB rats. The contribution of (Ss)-DS-ONJ to reducing inflammatory events is mediated by the inhibition of classical stress kinase pathways and the blocking of inflammasome complex activation. The (Ss)-DS-ONJ treatment is able to inhibit the epithelial-to-mesenchymal transition (EMT) progression, but only when the IL18 levels are reduced by the treatment. These findings suggest that (Ss)-DS-ONJ could be a novel, and multifactorial treatment for DN.

Adult kidney explants is a physiologic model for studying diabetic nephropathy

Inflammatory processes play a central role in the pathogenesis of diabetic nephropathy (DN) in the early stages of the disease. In vitro approach using cell lines help to understand the mechanisms involves and allow the molecular and biochemical processes. Adult kidney (AK) explants remain an essential instrument for advancing our understanding of the molecular and cellular regulation of signalling pathways from an organotipic view with physiological system interaction integrated. AK explants from T1DM animal model (BB rat) are obtained by slicing central kidney area preserving the organ's cytoarchitecture and reproduce the classical events detected during the DN in an in vivo model such as inflammation, epithelial-mesenchymal transition (EMT) processes by the modulation of a-SMA and e-Cadherin among others which have been determined by qRT-PCR, western-blot and immunohistochemistry. In this regard, AK explants reproduce the signalling pathways involve in DN progression (proinflammatory NFkB and inflammasome complex). This work demonstrates AK explants is a physiological experimental approach for studying the development and progression of DN. Furthermore, the inflammatory processes in AK explants under a diabetic environment and/or BB rats could be modulated by potential treatments for DN.

Potensi ekstrak daun pare (momordica charantia l.) sebagai alternatif meningkatkan kualitas hidup penderita Hepatitis B

Background: Hepatitis is a desease that can be transmitted through blood transfussion. Treatment for this infectious desease can be done with antibotics or chemotherapy. The use of other herbal can also minimize the negative impact of using chemical products. The research needs to be used as hepatitis drugs. According to previous research it was stated that pare (Momordica charantia L.) leaves showed hepatoprotective ability.
 Objective: to determine the potential of bitter melon leaf extract (Momordica charantia L.) in treating hepatitis B.
 Methods: This study is used completely randomized design with three treatments. Each of the six replications was treated as follows, normal control, positif control (giving parasetamol dosis 750 mg/kg BB rats. Giving extract pare leaves (dosis 100 mg/kg BB rats).
 Results: The results of the one-way ANOVA test (Oneway Anova) SGOT and SGPT showed that there was a very significant effect between the treatment of bitter melon leaf extract on the levels of SGOT in rats with a significance value of 0.000.
 Conclusion: The observation parameters are measurement of leaves SGOT and SGPT. The results showed that pare leaf extract has the potential as a hepatoprotector. It isi hoped that this research can provide information add insight into science to utilize plants as herbal medicine.

Anti-Inflammatory (M2) Response Is Induced by a sp2-Iminosugar Glycolipid Sulfoxide in Diabetic Retinopathy.

Diabetic retinopathy (DR) is one of the most common complications of Diabetes Mellitus (DM) and is directly associated with inflammatory processes. Currently, neuro-inflammation is considered an early event in DR and proceeds via microglia polarization. A hallmark of DR is the presence of retinal reactive gliosis. Here we report the beneficial effect of (S S,1R)-1-docecylsulfiny-5N,6O-oxomethylidenenojirimycin ((Ss)-DS-ONJ), a member of the sp2-iminosugar glycolipid (sp2-IGL) family, by decreasing iNOS and inflammasome activation in Bv.2 microglial cells exposed to pro-inflammatory stimuli. Moreover, pretreatment with (Ss)-DS-ONJ increased Heme-oxygenase (HO)-1 as well as interleukin 10 (IL10) expression in LPS-stimulated microglial cells, thereby promoting M2 (anti-inflammatory) response by the induction of Arginase-1. The results strongly suggest that this is the likely molecular mechanism involved in the anti-inflammatory effects of (S S)-DS-ONJ in microglia. (S S)-DS-ONJ further reduced gliosis in retinal explants from type 1 diabetic BB rats, which is consistent with the enhanced M2 response. In conclusion, targeting microglia polarization dynamics in M2 status by compounds with anti-inflammatory activities offers promising therapeutic interventions at early stages of DR.

The Vbeta13 T Cell Receptor Monoclonal Antibody Reduces Hyaluronan and CD68+, CD3+, and CD8+ Cell Infiltrations to Delay Diabetes in Congenic BB DRLyp/Lyp Rats.

The depleting Vβ13a T cell receptor monoclonal antibody (mAb) 17D5 prevents both induced and spontaneous autoimmune diabetes in BB rats. Here it was tested in congenic DRLyp/Lyp rats, all of which spontaneously developed diabetes. Starting at 40 days of age, rats were injected once weekly with either saline, His42 Vβ16 mAb, or 17D5 mAb and monitored for hyperglycemia. Diabetes occurred in 100% (n = 5/5) of saline-treated rats (median age, 66 days; range 55–73), and in 100% (n = 6/6) of His42-treated rats (median age, 69 days; range 59–69). Diabetes occurred in fewer (n = 8/11, 73%) 17D5-treated rats at a later age (median 76 days, range 60–92). Three (27%) of the 17D5-treated rats were killed at 101–103 days of age without diabetes (17D5 no-diabetes rats). Survival analysis demonstrated that 17D5 mAb delayed diabetes onset. Saline- and His42-treated rats had severely distorted islets with substantial loss of insulin-positive cells. These rats exhibited prominent hyaluronan (HA) staining, with the intra-islet HA+ accumulations measuring 5,000 ± 2,400 µm2 and occupying 36 ± 12% of islet area, and severe (grade 4) insulitis with abundant infiltration by CD68+, CD3+, and CD8+ cells. The 17D5 mAb-treated rats with delayed diabetes onset exhibited less severe insulitis (predominantly grade 3). In contrast, the 17D5 no-diabetes rats had mostly normal islets, with insulin+ cells representing 76 ± 3% of islet cells. In these rats, the islet HA deposits were significantly smaller than in the diabetic rats; the intra-islet HA+ areas were 1,200 ± 300 µm2 and accounted for 8 ± 1% of islet area. Also, islet-associated CD68+ and CD3+ cells occurred less frequently (on average in 60 and 3% of the islets, respectively) than in the diabetes rats (present in >95% of the islets). No CD8+ cells were detected in islets in all 17D5 no-diabetes rats. We conclude that mAb 17D5 delayed diabetes in DRLyp/Lyp rats and markedly reduced expression of HA and concomitant infiltration of CD68+, CD3+, and CD8+ cells. Our findings underscore the importance of refining immune suppression in prevention or intervention clinical trials to use mAb reagents that are directed against specific T cell receptors.

PENGARUH EKSTRAK RUMPUT LAUT (EUCHEMA SP.) TERHADAP HISTOLOGI SEL Β PANKREAS PADA RATTUS NOVERGICUS GALUR WISTAR DENGAN DIABETES MELLITUS YANG DI INJEKSI ALOKSAN

Metabolic diseases such as diabetes mellitus tends to increase, diabetes is not well controlled can cause oxidative stress. Oksidatf stress can increase ROS and antioxidants in our bodies may decrease, resulting in cell damage one pancreatic β cells. To overcome the effects of free radicals on penderit DM and the possibility of complications that need an exogenous antioxidants include seaweed. The purpose of this study was to determine the effect of seaweed extract (Euchema SP.) Against pancreatic β cell histology in wistar rats with alloxan-induced hyperglycemia.
 This research type experimental dalah Post Test Only Control Group Design conducted on 25 male rats aged 2-3 months ISTAR. Rats were divided into five kelompokyaitu 1 negative control group (KN) were given a standard diet, the first group of positive control (KP) induced alloxan in Intra Peritoneal 150 mg / kg, 3 Kelompom induced alloxan and given a seaweed extract (PI): 174mg / 200gr BB rats (P2): 352, 8 mg / 200 g BB rat, (P3): 529.2 mg / 200 g BB rats. The treatment was done for 48 days. Data were statistically processed using ANOVA test formula with a 95% confidence level.
 Results showed The average number of pancreatic β cells in the negative control (45.8 ± 8.871), the group of the positive controls (110 ± 1581) on the treatment kelompk occurred increasing the number of pancreatic beta cells, PI (176.6 ± 2.074), P2 (17.25 ± 2.02) P3 (30.6 ± 40.99). Annova test showed significant difference with P Value 0.0005 Alpha P ≤ 0.05. It is concluded that the extract of seaweed (Euchema SP.) On histological cell β pancreas in rats Wistar hyperglycemia induced by alloxan, the results of this study can be applied in humans, especially people with diabetes because it has been tested, it extracts umput sea can repair cells pancreatic β on the state of hyperglycemia.

Perbedaan Kadar Glutation (GSH) Hepar Tikus Putih Jantan (Rattus norvegicus) yang diinduksi Parasetamol Dosis Toksik dengan Pemberian Ekstrak Daun Kelor (Moringa oleifera)

Glutathione (GSH) transferase deficiency due to paracetamol exposure causes further oxidative stress to liver necrosis. To reduce oxidative stress that can cause damage to the liver of the body requires antioxidants. One plant to treat liver disease is the kelor leaf (because it has an active flavonoid material also has antioxidant activity). This study was conducted to determine the difference of glutathione hepar levels of male white rat induced paracetamol toxic dose by giving kelor leaf extract. The type of research is experimental laboratory in vivo with rancagan randomized post test only control group design. With the stages as follows 1.Leaf Extract Kelor with Ethanol 96%, 2.Perpeteration of experimental animals, 3.Treatment of experimental animals by giving extract of 3-dose of kelor leaf that is KP I 250 mg / 200 gr BB rat, KP II 500 mg / 200 gr BB rat, KP III 1000 mg / 200 gr BB rat for 14 days combined with paracetamol dose 2 gr / 200 gr BB rat compared with the negative control group (group given only paracetamol dose 2 gr / 200 gr BB rat) and control group positif only fed regular feed for 14 days). The result showed that there was a significant difference mean of GSH levels between all treatment groups obtained p = 0,000 (p <α) p values smaller than 0.05. There was the highest increase of GSH in treatment group II (142,7525 μmol / mg) and lowest dose of GSH in positive control group (57,1812 μmol / mg), dose paracetamol toxic dosage and kelor leaf extract 500 mg / gr BB rat can increase GSH hepar p = 0,000 (p <α) p less than 0 , 05. The conclusion of the test results showed that giving of kelor leaf extract at dose of treatment group II can increase GSH hepar level significantly

Test of Hepatoprotector Effect of Merak Leaf Ethanol Extract (Caesalpinia Pulcherrima L) with SGPT Enzyme Parameter and SGOT of Induced Parasetamol Heart Rats (Rattus Norvegicus)

Tests have been carried out research hepatoprotective Peacock Flower Leaves Ethanol Extract (Caesalpinia pulcherrima L) with Parameter enzymes SGOT and SGPT on Male Rat (Rattus norvegicus) induced Paracetamol. This study aims to assess the hepatoprotective effect of the ethanol extract of leaves of peacock flower (Caesalpinia pulcherrima L). In this study used 15 rats were divided randomly into 5 groups. Group I was given 1% CMC-Na as the control, group II was induced with paracetamol 1000 mg/kg for 3 days as the toxic dose to induce liver damage, group III, IV and V induced by paracetamol 1000 mg/kg for 3 days and then proceed with the extract ethanol leaf peacock flower (Caesalpinia pulcherrima L) for 7 days in a row with a dose of 270mg/200 g BB rats, 540mg/200 g BB rats, 1080mg/200 gram BB rats. Before treatment, the mice blood drawn through the lateral vein then measured the levels of SGPT and SGOT early. After day 8, re-performed blood sampling to measure the levels of SGPT and SGOT end.

EFEK PEMBERIAN GAMBIR (Uncaria gambir roxb.) TERSTANDARISASI DAN GAMBIR YANG BERASAL DARI PAYAKUMBUH TERHADAP PERBAIKAN TUKAK LAMBUNG PADA TIKUS PUTIH JANTAN

There has been a study of the standardized gambier effect (Uncaria gambir Roxb.) And gambir derived from Payakumbuh area on the improvement of gastric ulcers in male rats induced by absolute ethanol 1 ml / 200 g BB rat. This study was an experimental study using male white rats divided into 4 groups with dosage 1 x daily for 2 days. The group consisted of negative control, positive control, 2 treatment groups (Standardized gambir and gambir Payakumbuh) with a gambir dose of 300 mg / kg BW administered orally. The method used was rat induction method using ethanol absolute where the parameters observed were recovery of peptic ulcer and pH of stomach fluid to normal. The results showed that gambier (Uncaria gambir Roxb.) Had significant effect on povary index and pH (p <0,05), where standardized gambir group was better than gambir Payakumbuh to repair peptic ulcer.

Blueberry Supplementation Influences the Gut Microbiota, Inflammation, and Insulin Resistance in High-Fat-Diet–Fed Rats

BackgroundGut microbiota dysbiosis has been linked to obesity-associated chronic inflammation. Microbiota manipulation may therefore affect obesity-related comorbidities. Blueberries are rich in anthocyanins, which have anti-inflammatory properties and may alter the gut microbiota. ObjectiveWe hypothesized that blueberry supplementation would alter the gut microbiota, reduce systemic inflammation, and improve insulin resistance in high-fat (HF)-diet–fed rats. MethodsTwenty-four male Wistar rats (260–270 g; n = 8/group) were fed low-fat (LF; 10% fat), HF (45% fat), or HF with 10% by weight blueberry powder (HF_BB) diets for 8 wk. LF rats were fed ad libitum, whereas HF and HF_BB rats were pair-fed with diets matched for fiber and sugar contents. Glucose tolerance, microbiota composition (16S ribosomal RNA sequencing), intestinal integrity [villus height, gene expression of mucin 2 (Muc2) and β-defensin 2 (Defb2)], and inflammation (gene expression of proinflammatory cytokines) were assessed. ResultsBlueberry altered microbiota composition with an increase in Gammaproteobacteria abundance (P < 0.001) compared with LF and HF rats. HF feeding led to an ∼15% decrease in ileal villus height compared with LF rats (P < 0.05), which was restored by blueberry supplementation. Ileal gene expression of Muc2 was ∼150% higher in HF_BB rats compared with HF rats (P < 0.05), with expression in the LF group not being different from that in either the HF or HF_BB groups. Tumor necrosis factor α (Tnfa) and interleukin 1β (Il1b) gene expression in visceral fat was increased by HF feeding when compared with the LF group (by 300% and 500%, respectively; P < 0.05) and normalized by blueberry supplementation. Finally, blueberry improved markers of insulin sensitivity. Hepatic insulin receptor substrate 1 (IRS1) phosphorylation at serine 307:IRS1 ratio was ∼35% higher in HF rats compared with LF rats (P < 0.05) and HF_BB rats. ConclusionsIn HF-diet–fed male rats, blueberry supplementation led to compositional changes in the gut microbiota associated with improvements in systemic inflammation and insulin signaling.

Neither polyphenol-rich red wine nor fenofibrate affects the onset of type-1 diabetes mellitus in the BB rat

Serum levels of the pro-inflammatory apolipoprotein CIII (apoCIII) are increased in type-1 diabetic (T1D) patients and when β-cells are exposed to apoCIII they undergo apoptosis, which can be prevented by an antibody against apoCIII. We have previously investigated the BB rat, an animal model that develops a human-like T1D at the age of around 60 days, and found that apoCIII was also increased in sera from pre-diabetic rats and this promoted β-cell death. Lowering apoCIII with an oligonucleotide antisense during a phase of the pre-diabetic period prolonged the time to onset of T1D. In order to find other ways to lower apoCIII we in this study tested non-alcoholic red wine with medium and high concentrations of polyphenols and the lipid-lowering drug, fenofibrate, both reported to decrease the expression of apoCIII by activating peroxisome proliferator-activated receptors. Pre-diabetic BB-rats were treated orally for one month prior to the expected onset of diabetes with the two different wines or fenofibrate. None of the treatments prevented or prolonged the time to onset of diabetes and the expression of apoCIII was unaffected in this animal model for T1D. However, it must be emphasized that this does not exclude that other species can show a response to these substances.

THE EFFECTS OF CORN FLOUR WITH TEMPEH FLOUR SUPPLEMENTATION FEEDING IN DIABETES MELLITUS WISTAR RATS TOWARD BLOOD GLUCOSE LEVEL

Background: Diabetes mellitus (DM) is metabolic disorder syndrome characterized by hyperglycemia due to deficiency of insulin secretion. Patients of diabetic patients increases each year, so it needs proper handling. Corn flour is a source of carbohydrates with a low glycemic index to help reduce the rise in blood sugar levels. In addition, supplementation with tempeh flour containing isoflavones act to protect cells from free radical thereby inhibiting damage cells. Fiber in tempeh affect blood glucose levels because it slows the absorption of glucose.Objective: To determine the effect supplementation of corn flour with tempeh flour on blood sugar levels in diabetes mellitus Wistar rats.Methods: The study was true experimental design with Pre-posttest control group design, samples were 20 male Wistar rats aged 2-3 months were then divided into 4 groups (T0, T1, T2, T3.) T0 was injected with alloxan as 30 mg / 150 grams of BB rats are subsequently treated with standard diet; T1 was dministered by standard diet 50% + 50% corn flour; T2 was administered by standard diet 50% + 30% + corn flour tempeh flour 20%; and T3 was administered by standard diet of corn flour 50% + 15% + 35% tempeh flour for 2 weeks. Blood glucose levels were measured with a glucose kit (GOD FS). Research data were analyzed by One Way ANOVA followed by Tukey's Post Hoc test p-value &lt;0.05.Results: There were significant differences on blood sugar levels in all groups (p = 0.000): control group (only dietary standards), T1 (administered by standard diet 50% + corn flour 50%), T2 (administered by a standard diet 50% + cornstarch 30% tempeh flour + 20%) and T3 (administered by standard diet of corn flour 50% + 15% + 35% tempeh flour).Conclusion: corn flour with tempeh flour supplementation effect on decresing of blood sugar levels.

The β1-Adrenergic Receptor Blocker, Metoprolol, Improves Survival and Electrical Remodeling in Rats with Pulmonary Artery Hypertension

Right ventricular (RV) failure is the leading cause of death in patients with pulmonary arterial hypertension (PAH). Pre-clinical studies have shown that β-blockers can improve survival in PAH and RV failure, however effects on electrical remodeling are unknown.Male Wistar rats were injected with saline (controls, CON) or 60mg/kg of monocrotaline (MCT) to induce PAH and RV failure. Metoprolol (10mg/kg) or placebo was administered daily from day 15 post MCT injection. For the acquisition of in vivo ECG measurements telemetric devices were implanted in CON, placebo treated MCT (FAIL) and β-blocker treated MCT (BB). Rats were removed when heart failure symptoms developed. Recordings occurred daily during light and dark cycles.Survival of the BB rats was significantly improved with a median time to failure of 32 days post injection compared to the FAIL rats median of 23 days (P BB > CON with all groups significantly different to each other (P< 0.05-0.001). The time from T-wave peak to end (Tpe) followed the same pattern but FAIL and BB were not significantly different from each other (P< 0.05-0.01), N = 9-10 animals in each group.We show that β1-blockade delays the onset of HF in PAH rats. In addition it partially reverses the increase in action potential duration (QT interval) possibly by reversing effects on K+ channel expression. There also was a trend for reduced dispersion of repolarisation (Tpe). These effects could help reduce pro-arrhythmic substrates of PAH rat hearts.Supported by the British Heart Foundation

Experimental Diabetes Mellitus in Different Animal Models.

Animal models have historically played a critical role in the exploration and characterization of disease pathophysiology and target identification and in the evaluation of novel therapeutic agents and treatments in vivo. Diabetes mellitus disease, commonly known as diabetes, is a group of metabolic disorders characterized by high blood glucose levels for a prolonged time. To avoid late complications of diabetes and related costs, primary prevention and early treatment are therefore necessary. Due to its chronic symptoms, new treatment strategies need to be developed, because of the limited effectiveness of the current therapies. We overviewed the pathophysiological features of diabetes in relation to its complications in type 1 and type 2 mice along with rat models, including Zucker Diabetic Fatty (ZDF) rats, BB rats, LEW 1AR1/-iddm rats, Goto-Kakizaki rats, chemically induced diabetic models, and Nonobese Diabetic mouse, and Akita mice model. The advantages and disadvantages that these models comprise were also addressed in this review. This paper briefly reviews the wide pathophysiological and molecular mechanisms associated with type 1 and type 2 diabetes, particularly focusing on the challenges associated with the evaluation and predictive validation of these models as ideal animal models for preclinical assessments and discovering new drugs and therapeutic agents for translational application in humans.

A robust method for assessing chemically induced mutagenic effects in the oral cavity of transgenic Big Blue® rats.

The Big Blue® (BB) in vivo mutation assay uses transgenic rodents to measure treatment-induced mutations in virtually any tissue. The BB assay can be conducted in rats or mice and is ideal for investigating tissue-specific mutagenic mode of action of tumor induction. Some tissues such as oral mucosa have not been thoroughly studied. Due to the small quantity and cartilaginous nature of oral cavity tissues, development of special prosection and DNA isolation methods was required to permit robust analysis of mutations in these tissues. Improved surgical methods permitted collection of adequate and reproducible quantities of tissue (∼45 mg gingiva/buccal and ∼30 mg gingiva/palate). Optimized DNA isolation methods included use of liquid nitrogen pulverization, homogenization, nuclei pelleting, digestion, and phenol/chloroform extraction, to yield sufficient quantities of DNA from these tissues. In preliminary optimization work, mutant frequency (MF) in tongue and gingiva was increased in rats exposed to the promutagen, benzo[a]pyrene, and the direct mutagen, N-ethyl-N-nitrosourea. The oral cavity carcinogen, 4-nitroquinoline-1-oxide (4-NQO; 10 ppm in drinking water; 28 days), was qualified as a positive control for mutagenesis in oral tissues since it caused significant increases in cII MFs in gingiva/palate (50.2-fold) and gingiva/buccal tissues (21.3-fold), but not in liver or bone marrow (0.9- and 1.4-fold, respectively). These results are consistent with the observation that 4-NQO primarily induces tumors in oral cavity. Results also demonstrate the utility of the BB rat mutation assay and optimized methods for investigation of oral cavity mutagenicity, and by extension, analysis of other small and cartilaginous tissues.

Lipid droplets hypertrophy: a crucial determining factor in insulin regulation by adipocytes.

Lipid droplets (LDs) hypertrophy in adipocytes is the main cause of energy metabolic system dysfunction, obesity and its afflictions such as T2D. However, the role of adipocytes in linking energy metabolic disorders with insulin regulation is unknown in humans. Human adipocytes constitutively synthesize and secrete insulin, which is biologically functional. Insulin concentrations and release are fat mass- and LDs-dependent respectively. Fat reduction mediated by bariatric surgery repairs obesity-associated T2D. The expression of genes, like PCSK1 (proinsulin conversion enzyme), GCG (Glucagon), GPLD1, CD38 and NNAT, involved in insulin regulation/release were differentially expressed in pancreas and adipose tissue (AT). INS (insulin) and GCG expression reduced in human AT-T2D as compared to AT-control, but remained unchanged in pancreas in either state. Insulin levels (mRNA/protein) were higher in AT derived from prediabetes BB rats with destructed pancreatic β-cells and controls than pancreas derived from the same rats respectively. Insulin expression in 10 human primary cell types including adipocytes and macrophages is an evidence for extrapancreatic insulin-producing cells. The data suggest a crosstalk between AT and pancreas to fine-tune energy metabolic system or may minimize the metabolic damage during diabetes. This study opens new avenues towards T2D therapy with a great impact on public health.

Transplantation of Pancreatic Islets Immobilized in Alginate-Based Microcapsules: From Animal Studies to Clinical Trials

Microencapsulated islet transplantation has been investigated for over three decades in an attempt to eliminate the hostile effects of long-term immunosuppressant usage and improve islet engraftment in patients suffering from Type 1 Diabetes Mellitus (T1DM). Once feasibility of the islet encapsulation process was confirmed, the biocompatibility and survival of microencapsulated islets were directly tested in different animal models. Such animal models include: immunodeficient rodents (nude and NOD-SCID mice), immunocompetent rodents, autoimmune diabetic rodents (NOD mice and BB rats), and large animals (dogs, pigs, and non-human primates). In general, the majority of microcapsules tested in vivo was found to be biocompatible with the host and retained their function. This was especially apparent in small animal models. However, greater variability and reduced biocompatibility was observed in larger animal models. Since the first attempts to introduce this methodology to the clinical field, different devices and several implementation techniques have been proposed in order to support this technology. To date islet microencapsulation in the absence of immunosuppressive medication has not yet successfully reached the clinical setting. The purpose of this review is to summarize the transplant outcomes of different microencapsulation systems and transplant models, to reveal the major obstacles that each has presented, and to propose better avenues of investigation into future studies, which may lead to a successful clinical application for this technology.

Susceptibility to Fatty Acid-Induced β-Cell Dysfunction Is Enhanced in Prediabetic Diabetes-Prone BioBreeding Rats: A Potential Link Between β-Cell Lipotoxicity and Islet Inflammation

β-Cell lipotoxicity is thought to play an important role in the development of type 2 diabetes. However, no study has examined its role in type 1 diabetes, which could be clinically relevant for slow-onset type 1 diabetes. Reports of enhanced cytokine toxicity in fat-laden islets are consistent with the hypothesis that lipid and cytokine toxicity may be synergistic. Thus, β-cell lipotoxicity could be enhanced in models of autoimmune diabetes. To determine this, we examined the effects of prolonged free fatty acids elevation on β-cell secretory function in the prediabetic diabetes-prone BioBreeding (dp-BB) rat, its diabetes-resistant BioBreeding (dr-BB) control, and normal Wistar-Furth (WF) rats. Rats received a 48-h iv infusion of saline or Intralipid plus heparin (IH) (to elevate free fatty acid levels ~2-fold) followed by hyperglycemic clamp or islet secretion studies ex vivo. IH significantly decreased β-cell function, assessed both by the disposition index (insulin secretion corrected for IH-induced insulin resistance) and in isolated islets, in dp-BB, but not in dr-BB or WF, rats, and the effect of IH was inhibited by the antioxidant N-acetylcysteine. Furthermore, IH significantly increased islet cytokine mRNA and plasma cytokine levels (monocyte chemoattractant protein-1 and IL-10) in dp-BB, but not in dr-BB or WF, rats. All dp-BB rats had mononuclear infiltration of islets, which was absent in dr-BB and WF rats. In conclusion, the presence of insulitis was permissive for IH-induced β-cell dysfunction in the BB rat, which suggests a link between β-cell lipotoxicity and islet inflammation.