Pancreatic Tissue Homogenate Research Articles

Preparation of bee venom-loaded chitosan nanoparticles for treatment of streptozotocin-induced diabetes in male Sprague Dawley rats

BackgroundDiabetes mellitus (DM) can be defined as an increase in the blood sugar level and a disturbance in protein, fat and carbohydrate metabolism. Bee venom (BV) is useful for treating and preventing diabetic rats’ histological and biochemical problems. Although the medical advantages of BV have been identified, its safety has remained a substantial barrier for its application. Consequently, the goal of our work was to prepare bee venom-loaded chitosan (BV-CS) nanoparticles (NPs), which would then be physically characterized. This was followed by examining the effect of the synthetized BV-CS NPs on oxidation, inflammation and coagulation in vitro. In diabetic rats’ model [induced by streptozotocin (STZ)], the produced BV-CS NPs were tested as an anti-diabetic medication.ResultsIn vivo testing on pancreatic tissue homogenates showed that BV-CS NPs have antioxidant and anti-inflammatory properties. The results showed that BV-CS NPs can be used as a safe and efficient therapy for diabetes. Up to a concentration of 250 µg/ml, the generated NPs demonstrated potential antioxidant, membrane stabilizing, and non-cytotoxic capabilities. Our findings indicated that the administration of BV-CS NPs significantly controlled blood glucose levels and metabolic abnormalities that accompanied diabetes induction.ConclusionsBV-CS NPs were successful in treating STZ-induced diabetes in rats, stimulated insulin secretion and were safe to be used in vivo.Graphical abstract

Therapeutic effect of oral insulin-chitosan nanobeads pectin-dextrin shell on streptozotocin-diabetic male albino rats

The current study inspects the therapeutic effects of orally ingested insulin-loaded chitosan nanobeads (INS-CsNBs) with a pectin-dextrin (PD) coating on streptozotocin (STZ)-induced diabetes in Wistar rats. The study also assessed antioxidant effects in pancreatic tissue homogenate, insulin, C-peptide, and inflammatory markers interleukin-1 beta and interleukin-6 (IL-1β and IL-6) in serum. Additionally, histopathological and immunohistochemical examination of insulin granules, oxidative stress, nuclear factor kappa B (NF-κB P65), and sirtuin-1 (SIRT-1) protein detection, as well as gene expression of nuclear factor erythroid 2–related factor 2 (Nrf2), heme oxygenase-1 (HO-1), B-cell lymphoma 2 (Bcl2), and Bcl-2-associated X protein (Bax) in pancreatic tissue were investigated. After induction of diabetes with STZ, rats were allocated into 6 groups: the normal control (C), the diabetic control (D), and the diabetic groups treated with INS-CsNBs coated with PD shell (50 IU/kg) (NF), free oral insulin (10 IU/kg) (FO), CsNBs-PD shell (50 IU/kg) (NB), and subcutaneous insulin (10 IU/kg) (Sc). The rats were treated daily for four weeks. Treatment of diabetic rats with INS-CsNBs coated with PD shell resulted in a significant improvement in blood glucose levels, elevated antioxidant activities, decreased NF-κB P65, IL-1β, and IL-6 levels, upregulated Nrf-2 and HO-1, in addition to a marked improvement in the histological architecture and integrity compared to the diabetic group. The effects of oral INS-CsNBs administration were comparable to those of subcutaneous insulin. In conclusion, oral administration of INS-loaded Cs-NBs with a pectin-dextrin shell demonstrated an ameliorative effect on STZ-induced diabetes, avoiding the drawbacks of subcutaneous insulin.

THE EFFECT OF CHRONIC IMMOBILIZATION STRESS ON THE CONTENT OF MICRO- AND MACROELEMENTS IN THE PANCREAS AND BLOOD SERUM OF RATS AND THEIR NEWBORN OFFSPRING

Have been considered the role of macro- and microelements - Ca, Mg, Zn, Fe, and Cu imbalance in the blood serum and pancreatic tissue homogenate of rats, whose pregnancy took place against the background of chronic immobilization stress and their newborn

Розподіл серинових протеаз у плазмі крові та підшлунковій залозі за хронічного панкреатиту та онкопатології

The aim of our study was to evaluate the trypsin-like serine proteases (TLPs) distribution between systemic circulation and pancreatic tissue and to investigate the peculiarities of their involvement in the extracellular matrix components degradation in patients with pancreatic pathologies with electrophoretic analysis methods using. Тhe Khmelnitsky Regional Clinical Hospital patients aged 28-89 were selected for this study: 20 people with chronic pancreatitis (group CP); 20 people with pancreatic cancer (group PC); 20 conditionally healthy persons (control). Blood plasma samples and pancreatic tissue homogenates were obtained from all the patients, from which the TLPs fractions were subsequently obtained by the affinity chromatography method. The study showed that TLPs content in the blood plasma of patients with pancreatic pathologies is higher, and in tissue homogenates is lower relative to the values of the corresponding indicators in the control. Disk-electrophoresis using showed that TLPs fractions obtained from the blood plasma of patients of all studied groups contain a lot of high molecular weight (HMW) proteins, while TLPs from the pancreatic tissue homogenates of patients with pancreatic pathologies mainly consists of low molecular weight (LMW) proteins. Enzyme-electrophoresis results showed that all TLPs fractions include enzymes with fibrinogenolytic, gelatinolytic and collagenolytic activity. In plasma, the first were represented by medium molecular weight (MMW) proteins, and the last two groups included a lot of HMW proteins as well as proteins with very high molecular weight. In homogenates, fibrinogenolytic activity was characteristic for LMW proteins only, whereas gelatinases and collagenases were represented by both MMW and LMW proteins. Our results indicate the differences in the TLPs fractions components obtained from blood plasma and pancreatic tissue of patients with investigated pathologies, as well as significant distinctions in the processes of extracellular matrix remodeling under СР and РС.

Вміст тригерних компонентів системи протеолізу та їхніх регуляторів при розвитку патологій підшлункової залози

The content of the plasminogen activation system components (plasminogen, plasminogen tissue activator, and its inhibitor PAI-1) was investigated as well as the concentration of thrombomodulin, protein C, matrix metalproteinases (MMP -1, -2, -3, -8, -9, -10) and their inhibitor TIMP, growth factors content (such as transforming growth factor-β1, insulin-like growth factor-1, fibroblasts growth factor-2) and cytokine profile (interleukines IL-1β, -4, -6, -8, -10, tumor necrosis factor, interferon-γ in patients with chronic pancreatitis (CP) and pancreatic cancer (PC) were established. Khmelnitsky Regional Clinical Hospital patients aged 28-89 were selected for this study: 20 people with chronic pancreatitis (group CP); 20 people with pancreatic cancer (group PC); 20 conditionally healthy persons (control). Blood plasma samples and pancreatic tissue homogenates were obtained from all the patients. The studied indicators’ content in the experimental materials was determined by the enzyme-linked immunosorbent assay using appropriate antibodies. At the level of systemic circulation, a statistically significant increase was found in most of the studied parameters under the CP conditions. However, PC was characterized by an increase of two blood plasma indications only (thrombomodulin and protein C). In contrast, the pancreatic sample tissue examination for both aforementioned pathologies revealed significant changes in the content of most metalloproteinases and cytokines under PC. This indicates the development of metastasis, angiogenesis, and immunomodulation-aimed local biochemical processes in the affected organ.

Niclosamide as a Prospective Therapeutic in L-Arginine Induced Acute Pancreatitis in Rats; Concerning Autophagic p62/ NF-kB signaling pathway

Autophagic flux impairment is recently reported as a cardinal factor in acute pancreatitis (AP)pathogenesis. Niclosamide, an anthelmintic drug, has been lately proved to be a potent autophagyenhancer. The diminution of the various inflammatory factors unrestrained release via autophagyimprovement may be helpful to improve the prognosis of AP. This study spots on investigating thepotential ameliorative effect of niclosamide on autophagic flux and its consequent curative outcomeon L-arginine-induced AP in rats. Thirty male wistar rats were divided into three groups. The first oneis the control one, the second is L-arginine induced AP group, the third group is niclosamide treatedL-arginine induced AP. Serum lipase, amylase, pancreatic tissue homogenate IL6, IL1β, TNFα, NF-kB,oxidative stress biomarkers; glutathione peroxidase activity, Hydroxy-2’-Deoxy-Guanosine and totalantioxidant capacity levels were evaluated. Besides, the DNA-binding activity of nuclear erythroidrelated factor 2 (Nrf-2) was assessed using a pancreatic tissue nuclear extract. Both LC3-II subunit &P62 mRNA were quantified using PCR technique. Morphometric analysis of histopathological changeswas done. The obtained data showed that niclosamide improved L-arginine induced AP as evidencedby significantly reduced serum lipase and amylase levels, which could be related to improvement ofautophagy flux impairment as evidenced by decreased levels of LC3-II and p62 expression in pancreaticcells, in addition to anti-inflammatory effect as evidenced by decreased NF-kB and proinflammatorycytokines levels, along with improving the antioxidant capacity of the pancreatic tissue. As manifestedby elevation of Nrf-2- DNA binding activity and normalization of oxidative stress biomarkers levels.These results could pave the way for niclosamide as a potential therapeutic role in acute pancreatitis.

Syzygium aqueum (Burm.f.) Alston Prevents Streptozotocin-Induced Pancreatic Beta Cells Damage via the TLR-4 Signaling Pathway.

Although several treatments are available for the treatment of type 2 diabetes mellitus, adverse effects and cost burden impose the search for safe, efficient, and cost-effective alternative herbal remedies. Syzygium aqueum (Burm.f.) Alston, a natural anti-inflammatory, antioxidant herb, may suppress diabetes-associated inflammation and pancreatic beta-cell death. Here, we tested the ability of the bioactive leaf extract (SA) to prevent streptozotocin (STZ)-induced oxidative stress and inflammation in pancreatic beta cells in rats and the involvement of the TLR-4 signaling pathway. Non-fasted rats pretreated with 100 or 200 mg kg−1 SA 2 days prior to the STZ challenge and for 14 days later had up to 52 and 39% reduction in the glucose levels, respectively, while glibenclamide, the reference standard drug (0.5 mg kg−1), results in 70% reduction. Treatment with SA extract was accompanied by increased insulin secretion, restoration of Langerhans islets morphology, and decreased collagen deposition as demonstrated from ELISA measurement, H and E, and Mallory staining. Both glibenclamide and SA extract significantly decreased levels of TLR-4, MYD88, pro-inflammatory cytokines TNF-α, and TRAF-6 in pancreatic tissue homogenates, which correlated well with minimal pancreatic inflammatory cell infiltration. Pre-treatment with SA or glibenclamide decreased malondialdehyde, a sensitive biomarker of ROS-induced lipid peroxidation, and restored depleted reduced glutathione in the pancreas. Altogether, these data indicate that S. aqueum is effective in improving STZ-induced pancreatic damage, which could be beneficial in treating type 2 diabetes mellitus.

Possible ameliorative effects of silymarin on gibberellic acid-induced pancreatic dysfunction in adult female rats and their pups

Background: Gibberellic acid (GA3) is frequently applied in agriculture to stimulate flowering & fruit growth. Owing to its persistence in the soil for months, it may cause harm to human health. Silymarin is a herbal drug commonly known as hepatoprotective agent. Aim: To reveal the outcomes of exposure to GA3 on the pancreatic functions in late days of gestation and early lactation and to elucidate the possible protective role of silymarin on these alterations if present and the pathophysiological pathways. Materials and Methods: 18 lactating Albino rats & 18 pups were classified into control group, GA3-treated group: received GA3 dissolved in drinking water (55 mg/kg/day), and silymarin & GA3-treated group: administered both GA3 & 100 mg/kg silymarin during the last week of pregnancy & the first 2 weeks of lactation. Serum levels of glucose, insulin & amylase were measured. Pancreatic tissue homogenate was used for the assessment of malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT), interleukin-1β (IL-1β) & tumor necrosis factor-alpha (TNF-α). Additionally, pancreatic specimens were processed for histological examination. Results: Administration of GA3 impaired pancreatic functions in dams and pups namely, elevated serum levels of glucose and amylase & reduced insulin levels accompanied with significant increased oxidative stress & inflammatory markers in pancreatic homogenate and altered the general histological pancreatic appearance. Co-treatment with silymarin potently improved these biochemical & histological alterations. Conclusion: Silymarin attenuates GA3-induced alterations in pancreatic functions through cytoprotecting actions on pancreatic exo- and endo-crine cells.

Protein Isolates from Fermented Melon Seeds Promoted Differential Expression in Liver and Pancreas of Streptozotocin Induced Diabetic Male Wistar Rats

Diabetes mellitus (DM) is the most common endocrine disorder of human. However, the anti-diabetic activity of protein isolates from fermented plants seed for DM remains enigmatic. The prevalence of diabetes in Africa is exponentially increasing with more deaths occurring directly from diabetes mellitus or from its associated complications. The current study investigated the effect of Protein isolate from fermented melon seeds (Ogiri; OPI) of Cucumeropsis manni on blood glucose, hepatic and pancreatic protein profile, histopathological parameters, identification and characterisation of expressed proteins in streptozotocin (STZ)-induced diabetic rats. Thirty Male wistar rats were divided into nondiabetic control, STZ-diabetic control, STZ-Ogiri protein isolate supplemented group (STZ-OPI; 200 mg/kg diet), STZ-Ogiri protein isolate supplemented group (STZ-OPI; 600 g/kg diet) and STZ-glibenclamide treated group (STZ-GBN; 0.5 mg/kg diet). Diabetes was induced by a single injection of STZ (60 mg/kg BW) freshly dissolved in 0.1 mol/L citrate buffer (pH 4.5) into the intraperitonium. Diabetes was confirmed by measuring the fasting blood glucose concentration 48-h post-injection. The rats with blood glucose level above 290 mg/dL were considered to be diabetic. Ogiri protein isolates was supplemented in the diet for 6 weeks. The supplementation OPI reduced (P< 0.05) the blood glucose concentration of the STZ-induced diabetic rats. OPI supplemented groups had significantly higher percentage body weight gain. The high dose OPI supplemented group had a lowest liver protein concentration (19.39 mg/dl) but a significantly (P< 0.05) higher pancreas protein concentration when compared to all the diabetic control. Histological sections of examined tissue revealed accumulation of fat in the liver of diabetic rats and necrosis of the islet of Langerhans were observed in the pancreas. 1DE SDS-PAGE of hepatic and pancreatic tissue homogenates revealed differential expression of 150 kDa proteins in rats treated with 200 mg/kg body weight of OPI only and 20-25 kDa proteins in rats treated with 600 mg/kg body weight of OPI respectively. This result show that OPI supplementation may impose a direct or indirect inhibitory or post translational modification on specific proteins implicated in hyperglycemia and diabetes and as such be a potential antihyperglycemic agent in the management of diabetes.

EFFECTS OF CADMIUM, AN ENVIRONMENTAL AND OCCUPATIONAL POLLUTANT, ON LIPID PEROXIDATION IN RAT PANCREATIC TISSUE

Technological development, industrialization and economic development have improved living standards, but also increased toxic metal emissions in the living and working environment. The aim of this study is the monitoring of lipid peroxidation in case of acute intoxication by heavy metal cadmium and the protective role of α-lipoic acid. In this study, we used healthy albino Wistar female rats, two or three months old. Based on the results obtained in this study, we note that cadmium-induced intoxication increases the level of malondialdehyde (MDA) in the pancreatic tissue homogenate. MDA is a direct indication of lipid peroxidation. Alpha-lipoic acid suggests reduction and correction of the toxic effect of cadmium after its exposure.

Distinct pathophysiological cytokine profiles for discrimination between autoimmune pancreatitis, chronic pancreatitis, and pancreatic ductal adenocarcinoma

BackgroundDiscriminating between autoimmune pancreatitis (AIP), chronic pancreatitis (CP), and pancreatic ductal adenocarcinoma (PDAC) can be challenging. In this retrospective study, levels of serum and tissue cytokines were analyzed as part of the clinical strategy for the preoperative differentiation between AIP and PDAC. The identification of differential cytokine profiles may help to prevent unnecessary surgical resection and allow optimal treatment of these pathologies.MethodsTo compare the cytokine profiles of AIP, CP, and PDAC patients, serum and pancreatic tissue homogenates were subjected to multiplex analysis of 17 inflammatory mediators. In total, serum from 73 patients, composed of 29 AIP (14 AIP-1 and 15 AIP-2), 17 CP, and 27 PDAC, and pancreatic tissue from 36 patients, including 12 AIP (six AIP-1 and six AIP-2), 12 CP, and 12 PDAC, were analyzed.ResultsComparing AIP and PDAC patients’ serum, significantly higher concentrations were found in AIP for interleukins IL-1β, IL-7, IL-13, and granulocyte colony-stimulating factor (G-CSF). G-CSF also allowed discrimination of AIP from CP. Furthermore, once AIP was divided into subtypes, significantly higher serum levels for IL-7 and G-CSF were measured in both subtypes of AIP and in AIP-2 for IL-1β when compared to PDAC. G-CSF and TNF-α were also significantly differentially expressed in tissue homogenates between AIP-2 and PDAC.ConclusionsThe cytokines IL-1β, IL-7, and G-CSF can be routinely measured in patients’ serum, providing an elegant and non-invasive approach for differential diagnosis. G-CSF is a good candidate to supplement the currently known serum markers in predictive tests for AIP and represents a basis for a combined blood test to differentiate AIP and particularly AIP-2 from PDAC, enhancing the possibility of appropriate treatment.

Nano-curcumin safely prevents streptozotocin-induced inflammation and apoptosis in pancreatic beta cells for effective management of Type 1 diabetes mellitus.

Approaches to prevent selective and progressive loss of insulin-producing beta cells in Type 1 diabetes mellitus (T1DM) will help to manage this prevalent and devastating disease. Curcumin (CUR), a natural anti-inflammatory substance, suppresses diabetes-associated inflammation and cell death. However, very high doses need to be used because of poor oral bioavailability, making it difficult to translate the anti-inflammatory actions to clinical situations. We have prepared biodegradable nanosystems encapsulating curcumin (nCUR), resulting in at least nine-fold improvement in oral bioavailability. Here, we tested the ability of nCUR to prevent streptozotocin (STZ)-induced inflammation and apoptosis in pancreatic islets and beta cells, in rats. Non-fasted rats pretreated with 10 or 50mg·kg-1 nCUR 6h prior to STZ challenge had up to 37% reduction in the glucose levels, while plain CUR (50mg·kg-1 ) results in 12% reduction. This treatment with nCUR was accompanied by decreased islet or beta cell death, as shown by TUNEL assay and H&E staining. Both CUR and nCUR significantly decreased levels of inflammatory cytokines in pancreatic tissue homogenates that correlated well with minimal histiocytic infiltration. Pre-treatment with nCUR, but not CUR, decreased 8-oxo-2'-deoxyguanosine, a sensitive biomarker of ROS-induced DNA damage, in pancreas. In normal rodents, daily dosing for 28days, with nCUR (25-100mg·kg-1 ) did not cause any deleterious health issues by the carrier. Together, these data indicate a potentially translatable dose of nCUR that is safe and efficacious in improving beta cell function, which could prevent T1DM.

Influence of gallic acid on α-amylase and α-glucosidase inhibitory properties of acarbose

Acarbose is an antidiabetic drug which acts by inhibiting α-amylase and α-glucosidase activities but with deleterious side effects. Gallic acid (GA) is a phenolic acid that is widespread in plant foods. We therefore investigated the influence of GA on α-amylase and α-glucosidase inhibitory properties of acarbose (in vitro). Aqueous solutions of acarbose and GA were prepared to a final concentration of 25μM each. Thereafter, mixtures of the samples (50% acarbose + 50% GA; 75% acarbose+25% GA; and 25% acarbose+75% GA) were prepared. The results revealed that the combination of 50% acarbose and 50% GA showed the highest α-glucosidase inhibitory effect, while 75% acarbose+25% GA showed the highest α-amylase inhibitory effect. Furthermore, all the samples caused the inhibition of Fe2+-induced lipid peroxidation (in vitro) in rat pancreatic tissue homogenate, with the combination of 50% acarbose and 50% GA causing the highest inhibition. All the samples also showed antioxidant properties (reducing property, 2,2'-azino-bis (-3-ethylbenzthiazoline-6-sulphonate [ABTS*] and 1,1-diphenyl-2-picrylhydrazyl [DPPH] free radicals scavenging abilities, and Fe2+ chelating ability). Therefore, combinations of GA with acarbose could be employed as antidiabetic therapy, with a possible reduction of side effects of acarbose; nevertheless, the combination of 50% acarbose and 50% GA seems the best.

Exploring the role of Mycobacterium avium subspecies paratuberculosis in the pathogenesis of type 1 diabetes mellitus: a pilot study

BackgroundAlthough the etiology of Type 1 Diabetes mellitus (T1DM) has not been determined, genetic polymorphism in key genes, including SLC11A1, and association with Mycobacterium avium subspecies paratuberculosis (MAP) have been reported. We hypothesize that molecular mimicry between MAP Heat shock protein 65 K (Hsp65) and human Glutamic Acid Decarboxylase 65 K (GAD65) may be the trigger leading to autoimmune destruction of beta cells in patients exposed to MAP.MethodPeptide sequences of MAP Hsp65 and human GAD65 were investigated for amino acid sequence homology and cross reactivity. A total of 18 blood samples from T1DM and controls were evaluated for the presence of MAP.ResultsPeptide BLAST analysis revealed a 44% overall identity between MAP Hsp65 and GAD65 with 75% positives in a 16 amino acid region. PyMOL 3D-structural analyses identified the same 16 amino acid region as a potential epitope for antibody binding. Preliminary data suggests a cross reactivity between MAP Hsp65, and a healthy rat pancreatic tissue homogenate against plasma from T1DM patients and rabbit polyclonal anti-MAP IgG. Long-term culture of human blood resulted MAP detection in 3/10 T1DM and 4/8 controls whereas MAP IgG was detected in 5/10 T1DM samples and 3/8 non-diabetic controls.ConclusionThe high degree of homology between GAD65 and MAP Hsp65 in an antigenic peptide region supports a possible mycobacterial role in triggering autoimmune destruction of pancreatic cells in T1DM. Reactivity of T1DM patient sera with MAP Hsp65 supports this finding. Culture of MAP from the blood of T1DM patients is intriguing. Overall, the preliminary data are mixed and do not exclude a possible role for MAP in T1DM pathogenesis. A larger study including well-characterized controls is needed to investigate the intriguing question of whether MAP is associated with T1DM or not?

Selection of Suitable Prodrug Candidates for in vivo Studies via in vitro Studies; The Correlation of Prodrug Stability in Between Cell Culture Homogenates and Human Tissue Homogenates

To determine the correlations/discrepancies of drug stabilities between in the homogenates of human culture cells and of human tissues. Amino acid/dipeptide monoester prodrugs of floxuridine were chosen as the model drugs. The stabilities (half-lives) of floxuridine prodrugs in human tissues (pancreas, liver, and small intestine) homogenates were obtained and compared with ones in cell culture homogenates (AcPC-1, Capan-2, and Caco-2 cells) as well as human liver microsomes. The correlations of prodrug stability in human small bowel tissue homogenate vs. Caco-2 cell homogenate, human liver tissue homogenate vs. human liver microsomes, and human pancreatic tissue homogenate vs. pancreatic cell, AsPC-1 and Capan-2, homogenates were examined. The stabilities of floxuridine prodrugs in human small bowel homogenate exhibited the great correlation to ones in Caco-2 cell homogenate (slope = 1.0-1.3, r2 = 0.79-0.98). The stability of those prodrugs in human pancreas tissue homogenate also exhibited the good correlations to ones in AsPC-1 and Capan-2 cells homogenates (slope = 0.5-0.8, r2 = 0.58-0.79). However, the correlations of prodrug stabilities between in human liver tissue homogenates and in human liver microsomes were weaker than others (slope = 1.3-1.9, r2 = 0.07-0.24). The correlations of drug stabilities in cultured cell homogenates and in human tissue homogenates were compared. Those results exhibited wide range of correlations between in cell homogenate and in human tissue homogenate (r2 = 0.07 - 0.98). Those in vitro studies in cell homogenates would be good tools to predict drug stabilities in vivo and to select drug candidates for further developments. In the series of experiments, 5'-O-D-valyl-floxuridine and 5'-O-L-phenylalanyl-L-tyrosyl-floxuridine would be selected as candidates of oral drug targeting delivery for cancer chemotherapy due to their relatively good stabilities compared to other tested prodrugs.

Beneficial Effect of S-allylcysteine (SAC) on Blood Glucose and Pancreatic Antioxidant System in Streptozotocin Diabetic Rats

The aim of the present study was to evaluate the possible protective effects of S-allyl cysteine (SAC) on the antioxidant defense system of pancreas in streptozotocin(STZ) induced diabetes in rats. The levels of blood glucose and TBARS in plasma and pancreas were estimated in control and experimental groups of rats. To assess the changes in the cellular antioxidant defense system, the level of reduced glutathione in plasma and pancreas and activities of superoxide dismutase and catalase were assayed in pancreatic tissue homogenate. The levels of glucose, TBARS and enzymatic antioxidants were altered in diabetic rats. These alterations were reverted back to near control levels after the treatment of SAC. The antidiabetic and antioxidant effect of SAC was compared with glyclazide, a well-known hypoglycemic drug. These findings suggest that SAC treatment exerts a therapeutic protective nature in diabetes by decreasing oxidative stress.

Pancreatic neuronal melanocortin-4 receptor modulates serum insulin levels independent of leptin receptor

The leptin-regulated melanocortin (MC) system modulates energy homeostasis and hypothalamic MC neuronal circuits regulate insulin secretion. We therefore hypothesized that MC system components were present in the pancreas. In order to determine the veracity of the hypothesis, we examined c-Fos, melanocortin-4 receptor (Mc4r), and alpha-melanocyte-stimulating hormone (α-MSH) expression levels in nondiabetic (intact leptin receptor signaling) and Zucker diabetic fatty (ZDF; leptin receptor deficiency) rats. We infused rats via the third ventricle with the α-MSH analog Nle4, D-Phe7-α-MSH (NDP-MSH), a Mc4r agonist. Subsequently, both hypothalamic and pancreatic c-Fos and Mc4r mRNAs were upregulated. Likewise, immunohistochemical analysis showed that an increased Mc4r and α-MSH expression in nerves surrounding the pancreatic vasculature and islets. Increases in c-Fos, α-MSH, and Mc4r expression were independent of leptin receptor function. Conversely, serum insulin was significantly reduced by NDP-MSH treatment, an effect which was reversed by the Mc4r specific blocker HS014. Finally, proopiomelanocortin (POMC) mRNA, the precursor of α-MSH, was detected by RT-PCR in pancreatic tissue homogenates. These findings suggest that pancreatic Mc4r and autonomic neurons participate in a communication pathway between the central MC system and pancreatic islets to regulate insulin secretion.

Enhanced Insulin Sensitivity Induced by Bilateral Splachnicectomy: Could an Anti-Incretin Factor Be the Culprit?

Purpose: In the “insulo-pancreon-axis,” insulin secretion respectively enhances and depresses amylase and lipase enzymes. In addition, in the intrapancreatic ganglia, several neuropeptides modulate the cholinergic, adrenergic and hormonal influences exerted upon the pancreon and the Langerhans islets units. The aim of the present protocol is to evaluate the changes elicited by a bilateral splanchnicectomy on several blood parameters, (both basally and following an oral glucose tolerance test) and on protein and nucleic acid concentration in the pancreatic tissue homogenate. Methods: Twenty-one male Wistar rats (˜300 g) were allocated to a control, sham operated (Sh) (n=10) and to an experimental series, bilateral splanchnicectomy (Spl) (n=11). One month after nerve interruption, an oral glucose tolerance test was performed. Under i.p tiopental anesthesia, a 50% glucolin solution (4.5 ml/Kg) rat was intragastrically infused. Basal, 30 and 60 min blood samples drawn by orbital puncture were analyzed. Following aortic exsanguinations, complete autopsies were carried out and protein and nucleic acids were determined in pancreatic gland homogenate. Results: Glycemia (both basally and post-glucolin infusion) was significantly depressed in the Spl series in respect to the Sh group. In contrast, amylase and lipase values remained unchanged. The same happened with those of protein, DNA and RNA in the pancreatic homogenate. In has been demonstrated in the literature that splanchnicectomy does not modify blood insulin level. The present results demonstrate that this procedure does not modify amylase or lipase values. Similar findings were shown by us after performing different types of neural duodeno-pancreatic-disconnection (DPD). These findings are our basis to speculate that bilateral splanchnicectomy, as well as DPD, interferes with the tonic autonomic nerve influences exerted normally upon the release and/ or actions of a putative anti-incretin factor. A drop of an anti-incretin factor might probably clear, at receptor level, the physiological signaling actions of insulin, thus enhancing the sensitivity of this hormone. Conclusion: The enhanced insulin sensitivity triggered by splanchnicectomy is most probably due to a drop of an anti-incretin factor.

Alcohol Pretreatment Increases Hepatic and Pulmonary Injury in Experimental Pancreatitis

Background: Systemic complications including pancreatitis-associated lung injury (PALI) are critical factors that determine the outcome of severe necrotizing pancreatitis (SNP). The aim of the present study was to evaluate the role of chronicalcohol exposure on the development of PALI. Methods: 48 rats were fed either a Lieber deCarli control or alcohol diet for 6 weeks. After completion, SNP was induced by intraductal infusion of bile salt followed by intravenous infusion of cerulein over 6 h. Control animals received i.v. Ringer's solution. Intravital microscopy of the liver was performed 6 h after induction of SNP to evaluate hepatic perfusion and leukocyte adhesion. Serum parameters, edema, inflammation, and histological changes were evaluated at 12 h. IL-6 levels were evaluated in portal venous and systemic blood as well as in pancreatic tissue homogenates. Results: Alcohol pretreatment did not affect pancreatic injury in SNP. PALI was aggravated after alcohol ingestion. These animals showed increased hepatic microcirculatory disturbances, compared to SNP alone. IL-6 showed peak levels in SNP with alcohol pretreatment, although they were also elevated in SNP alone. Systemic levels of IL-6 were higher than in the portal vein. Conclusion: In SNP, alcoholic pretreatment increases pulmonary damage, while pancreatic injury is identical. The liver seems to participate in this effect by increased hepatic cytokine release.

Oral administration of taurine improves experimental pancreatic fibrosis

The mechanism of pancreatic fibrosis is unclear. Taurine is used in the clinical treatment of a wide variety of diseases, but its effect on improving pancreatic fibrosis is unknown. We examined whether a diet with added taurine improves pancreatic fibrosis induced by dibutyltin dichloride (DBTC) in an experimental chronic pancreatitis rat model. In addition, we examined the influence of taurine on pancreatic stellate cells. Pancreatic fibrosis was induced by DBTC. Rats were fed a taurine-containing diet or a normal diet and were killed at 4 weeks. Pancreatic stellate cells were isolated from male Wistar rats. Cultured pancreatic stellate cells were incubated with or without taurine chloramine. Type I collagen and transforming growth factor-beta1 secretion was evaluated by ELISA, and matrix metalloproteinase activity was assessed by gelatin zymography. Interleukin-6, interleukin-2, and transforming growth factor-beta1 levels in the supernatants of pancreatic tissue homogenates were measured. Pancreatic fibrosis induced by DBTC was improved remarkably by the oral administration of the taurine-containing diet. Taurine chloramine decreased type I collagen, transforming growth factor-beta1, and matrix metalloproteinases 2 of the pancreatic stellate cell culture supernatant. Increased interleukin-6 and decreased interleukin-2 were found in the supernatants of the pancreatic tissue homogenates of DBTC-induced pancreatitis rats compared with other groups. The oral administration of taurine improves pancreatic fibrosis. Taurine chloramine inhibits transforming growth factor-beta1 produced from activated pancreatic stellate cells and improves pancreatic fibrosis.