Female Syrian Golden Hamsters Research Articles

Gestational low dietary protein induces intrauterine inflammation and alters the programming of adiposity and insulin sensitivity in the adult offspring

Malnutrition associated with low dietary protein can induce gestational inflammation and sets a long-lasting metabolic impact on the offspring even after replenishment. The work investigated whether a low-protein diet (LPD) during pregnancy and lactation induces intrauterine inflammation and predisposes offspring to adiposity and insulin resistance in their adult life. Female Golden Syrian hamsters were fed LPD (10.0% energy from protein) or a control diet (CD, 20.0 % energy from protein) from preconception until lactation. All pups were switched to CD after lactation and continued until the end. Maternal LPD increased intrauterine inflammation by enhancing neutrophil infiltration, amniotic hsCRP, oxidative stress, and mRNA expression of NFκβ, IL8, COX2, and TGFβ in the chorioamniotic membrane (P<.05). The prepregnancy body weight, placental, and fetal weights, serum AST and ALT were decreased, while blood platelets, lymphocytes, insulin, and HDL were significantly increased in LPD-fed dams (P<.05). A postnatal switch to an adequate protein could not prevent hyperlipidemia in the 6-months LPD/CD offspring. The lipid profile and liver functions were restored over 10 months of protein feeding but failed to normalize fasting glucose and body fat accumulation compared to CD/CD. LPD/CD showed elevated GLUT4 expression & activated pIRS1 in the skeletal muscle and increased expression of IL6, IL1β, and p65-NFκB proteins in the liver (P<.05). In conclusion, present data suggest that maternal protein restriction may induce intrauterine inflammation and affect liver inflammation in the adult offspring by an influx of fats from adipose that may alter lipid metabolism and reduce insulin sensitivity in skeletal muscle.

Serum Raman spectroscopy in experimental carcinogenesis hamster buccal pouch model: Exploring early diagnostic capability

AbstractAbout two third of oral cancer cases present at advanced stages, emphasizing the need for screening tools for early diagnosis. Raman spectroscopy (RS) can prove an appropriate tool for early diagnosis as biochemical changes occur before morphological changes. Due to limitations with study of early oral cancer stages in human subjects, we performed a sequential carcinogenesis study in animal model. In the present study, we aim to probe early biochemical changes occurring during DMBA induced oral carcinogenesis in hamster buccal pouch model, using serum RS (SRS). Serum being systemic biofluid can reflect the true in vivo state, is minimally invasive and offers advantages of remote diagnosis and serial sampling. The female Syrian golden hamsters were treated with 0.5% DMBA and retro‐orbital blood collection was performed every week for a period of 14 weeks. An increase in classification efficiency as the DMBA treatment progressed, with distinct classification of &gt;70% seen as early as week 5 (W5), appreciably early to development of visual changes (W8–W10) was observed. Furthermore, the early treatment weeks (W1–W4) and healthy condition (W0) show no misclassifications with weeks exhibiting frank tumours (W9–W14), demonstrating efficacy of SRS to stratify healthy versus carcinogen exposure. The findings suggest that as oral carcinogenesis progresses, biochemical alterations in serum such as increasing protein and loss of lipid content can be detected by RS, highlighting the feasibility and utility of SRS in early oral cancer diagnosis. To our knowledge, this is the first study exploring the ex vivo sequential approach to gain insights into oral cancer progression.

Microgliosis and neuronal proteinopathy in brain persist beyond viral clearance in SARS-CoV-2 hamster model.

SummaryBackgroundNeurological symptoms such as cognitive decline and depression contribute substantially to post-COVID-19 syndrome, defined as lasting symptoms several weeks after initial SARS-CoV-2 infection. The pathogenesis is still elusive, which hampers appropriate treatment. Neuroinflammatory responses and neurodegenerative processes may occur in absence of overt neuroinvasion.MethodsHere we determined whether intranasal SARS-CoV-2 infection in male and female syrian golden hamsters results in persistent brain pathology. Brains 3 (symptomatic) or 14 days (viral clearance) post infection versus mock (n = 10 each) were immunohistochemically analyzed for viral protein, neuroinflammatory response and accumulation of tau, hyperphosphorylated tau and alpha-synuclein protein.FindingsViral protein in the nasal cavity led to pronounced microglia activation in the olfactory bulb beyond viral clearance. Cortical but not hippocampal neurons accumulated hyperphosphorylated tau and alpha-synuclein, in the absence of overt inflammation and neurodegeneration. Importantly, not all brain regions were affected, which is in line with selective vulnerability.InterpretationThus, despite the absence of virus in brain, neurons develop signatures of proteinopathies that may contribute to progressive neuronal dysfunction. Further in depth analysis of this important mechanism is required.FundingFederal Ministry of Health (BMG; ZMV I 1-2520COR501), Federal Ministry of Education and Research (BMBF 01KI1723G), Ministry of Science and Culture of Lower Saxony in Germany (14 - 76103-184 CORONA-15/20), German Research Foundation (DFG; 398066876/GRK 2485/1), Luxemburgish National Research Fund (FNR, Project Reference: 15686728, EU SC1-PHE-CORONAVIRUS-2020 MANCO, no > 101003651).

Fructooligosaccharide ameliorates high-fat induced intrauterine inflammation and improves lipid profile in the hamster offspring

Maternal high-fat diet (HFD) often results in intrauterine and feto-placental inflammation, and increases the risks of fetal programming of metabolic diseases. Intake of prebiotic is reported beneficial. However, its effects on HFD during pregnancy and lactation is not known. We evaluated the maternal intake of fructooligosaccharide (FOS) and its impact on placental inflammation, offspring's adiposity, glucose, and lipid metabolism in their later life. Female Golden Syrian hamsters were fed with a control diet (CD, 26.4 % energy from fat) or HFD (60.7% energy from fat) in the presence or absence of FOS from preconception until lactation. All pups were switched over to CD after lactation and continued until the end. Placental inflammation was upregulated in HFD-fed dam, as measured by a high concentration of hsCRP in the serum and amniotic fluid. Neutrophil infiltration was significantly increased in the decidua through the chorionic layer of the placenta. The expression of pro-inflammatory cytokines such as COX2, NFκβ, IL-8, TGFβ mRNA was increased in the chorioamniotic membrane (P <.05). The HFD/CD hamsters had more adiposity, higher triglyceride, and low HDL at 12 months of age compared to CD/CD (P <.05). However, HFD+FOS/CD-fed hamsters prevented adverse effects such as placental inflammation, neutrophil infiltration, glucose, and lipid profiles in the offspring (P <.05). Anti-inflammatory and lipid-lowering effects of FOS may reduce placental inflammation by lowering neutrophil infiltration and decreasing the production of pro-inflammatory cytokines. Intake of FOS during pregnancy may be beneficial in maintaining lipid metabolism and preventing excess adiposity for mother and their offspring.

Progression and Resolution of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in Golden Syrian Hamsters

To catalyze severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research, including development of novel interventive and preventive strategies, the progression of disease was characterized in a robust coronavirus disease 2019 (COVID-19) animal model. In this model, male and female golden Syrian hamsters were inoculated intranasally with SARS-CoV-2 USA-WA1/2020. Groups of inoculated and mock-inoculated uninfected control animals were euthanized at 2, 4, 7, 14, and 28 days after inoculation to track multiple clinical, pathology, virology, and immunology outcomes. SARS-CoV-2–inoculated animals consistently lost body weight during the first week of infection, had higher lung weights at terminal time points, and developed lung consolidation per histopathology and quantitative image analysis measurements. High levels of infectious virus and viral RNA were reliably present in the respiratory tract at days 2 and 4 after inoculation, corresponding with widespread necrosis and inflammation. At day 7, when the presence of infectious virus was rare, interstitial and alveolar macrophage infiltrates and marked reparative epithelial responses (type II hyperplasia) dominated in the lung. These lesions resolved over time, with only residual epithelial repair evident by day 28 after inoculation. The use of quantitative approaches to measure cellular and morphologic alterations in the lung provides valuable outcome measures for developing therapeutic and preventive interventions for COVID-19 using the hamster COVID-19 model.

Influence of maternal hypercholesterolemia and phytosterol intervention during gestation and lactation on dyslipidemia and hepatic lipid metabolism in offspring of Syrian golden hamsters.

Although there is a normal physiological rise in maternal lipids during pregnancy, excessive maternal hyperlipidemia during pregnancy increases cardiovascular disease risk for both the mother and offspring. There are limited safe lipid-lowering treatment options for use during pregnancy, therefore, we evaluated the influence of maternal phytosterol (PS) supplementation on lipid and lipoprotein metabolism in mothers and progeny. Female Syrian golden hamsters were randomly assigned to three diets throughout prepregnancy, gestation, and lactation (n = 6/group): (i) Chow (Chow), (ii) chow with 0.5% cholesterol (CH), and (iii) chow with 0.5% CH and 2% PS (CH/PS). Compared with newly weaned pups from Chow dams, pups from dams fed the CH-enriched diet demonstrated increases (p < 0.05) in total-C, LDL-C, HDL-C, and total LDL and VLDL particle number. Pups from CH-fed mothers also exhibited higher hepatic CH concentration and differential mRNA expression pattern of CH regulatory genes. Pups from PS-supplemented dams demonstrated reductions (p < 0.05) in serum total-C, non-HDL-C, and LDL-C but also increased triglycerides compared with pups from CH-fed dams. Maternal PS supplementation reduced (p < 0.05) hepatic CH and increased the abundance of HMG-CoAr and LDLr protein in newly weaned pups compared with the CH group. Results suggest that maternal PS supplementation is largely effective in normalizing CH in pups born to mothers with hypercholesterolemia, however, the cause and long-term influence of increased triglyceride is not known.

Early Exposure to Phytosterols Protects Offspring from Hypercholesterolemia Induced by Maternal Cholesterol Feeding in Syrian Golden Hamsters

Pronounced maternal hyperlipidemia during pregnancy is a health concern as it produces offspring who are predisposed to dyslipidemia. As the use of lipid-lowering drugs during pregnancy is contraindicated, lipid-lowering compounds such as phytosterols (PS), plant-based cholesterol-lowering agents, should be examined as a potential means to reduce gestational dyslipidemia. We evaluated in utero and postnatal phytosterol exposure as a novel strategy to protect against hyperlipidemia in offspring. Female Syrian golden hamsters were randomly assigned to three diets throughout pre-pregnancy (2 weeks), gestation, and lactation (n=6/group): (i) Chow only, (ii) chow with 0.5% cholesterol (CH), and (iii) chow with 0.5% cholesterol and 2% PS (CH/PS).Pups from CH-fed dams demonstrated increased (p<0.05) total-C (+51%), LDL-C (+87%), HDL-C (+10%), and LDL particle number (+104%) compared with pups from chow-fed dams. Pups from PS-supplemented dams were protected from maternal CH feeding with reductions (p<0.05) in total-C (-30%) and LDL-C (-33%) concentrations. Maternal PS-supplementation did not alter (p>0.05) LDL particle number compared with pups from CH-fed dams. Hepatic cholesterol was increased in pups from CH-fed dams (57.9 ± 3.9 vs. 8.1 ± 0.7 mmol/g) but normalized in pups from PS-supplemented dams (7.8 ± 0.3 mmol/g). Results suggest that early exposure to PS in utero and throughout lactation can protect offspring from elevated cholesterol that is induced by maternal hypercholesterolemia. National Institute for Complementary and Alternative Medicine.

Flaxseed reverses atherosclerotic lesion formation and lowers lipoprotein(a) in ovarian hormone deficiency

The incidence of cardiovascular disease dramatically increases during menopause, and postmenopausal women seek natural alternatives to hormone therapy. Flaxseed can slow the progression of atherosclerotic lesion formation; however, it is not known whether it can reverse formation that has already occurred. Seventy-two female Golden Syrian hamsters were randomly divided into six groups (n = 12), sham-operated (sham) or ovariectomized (ovx), and kept on the same diet for 120 days to allow for atherosclerotic lesion development. After this 120-day period, whole flaxseed was introduced to the diets of hamsters in three of the groups: group 1 (sham + casein); group 2 (ovx + casein); group 3 (ovx + 7.5% flaxseed); group 4 (ovx + 15% flaxseed); group 5 (ovx + 22.5% flaxseed); and group 6 (ovx + 17β-estradiol). This diet was maintained for an additional 120 days. Lesion regression was examined histologically, and serum was analyzed for total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, Apo A, Apo B, and lipoprotein(a). Results showed that 15% and 22.5% flaxseed, compared with ovx animals, significantly reduced lipoprotein(a) (4.4 mg/dL [ovx] vs 2.15 mg/dL [15% flaxseed] and 0.3 mg/dL [22.5% flaxseed]; P < 0.05) and Apo B (2.8 mg/dL [ovx] vs 2.4 mg/dL [15% flaxseed] and 2.5 mg/dL [22.5% flaxseed]). Flax reduced by 67% the number of animals with aortic arch lesions. All three doses of flax reduce the severity of lesion formation compared with ovx controls. These results support the efficacy of flaxseed in reducing cardiovascular disease risk.

A novel tissue for islet transplantation in diabetics

BackgroundIslet transplantation for diabetes therapy has remained a challenge. None of the currently used transplantation sites have provided satisfactory results as islets seem to require a specific tissue for survival and growth. Since the submandibular gland (SMG) shares physiological and anatomical similarities with the pancreas, we attempted to use this tissue as the transplantation site. MethodsIn Experiment 1, a group of 10 female Syrian Golden hamsters’ (SGH) received isolated and purified homologous islets transplanted into their right SMG. In Experiment 2, 15 female SGH received islet transplant into their left SMG as above, except that the recipient hamsters were made diabetic by streptozotocin (STZ) before islet transplantation. In Experiment 3, isolated and purified human islets were transplanted into the SMG of 10 female hamsters. ResultsIn 8 out of 10 hamsters in Experiment 1 the islets survived and showed the same morphological structure and endocrine cell content, as intrapancreatic islets and presented signs of rapid growth and distribution. Also, as in Experiment 1, well-established islets were present in Experiment 2. Ten of the 15 hamsters pretreated with STZ had blood glucose values between 96 and 125 mg/dl, whereas three hamsters remained hyperglycemic (glucose levels between 194 and 417 mg/dl). Remarkably, the islets in the pancreas of 10 STZ-treated hamsters with functioning SMG islets remained atrophic even after 12 weeks. In two hamsters transplanted islets showed degeneration and remained diabetic until their pancreatic islets regenerated. In Experiment 3, transplanted human islets were completely destroyed. ConclusionsSMG appears to be the most suitable site for islet transplantation for the treatment of diabetes.

Enhancement of Carcinogenesis and Fatty Infiltration in the Pancreas in N-Nitrosobis(2-Oxopropyl)Amine-Treated Hamsters by High-Fat Diet

Obesity is associated with increased pancreatic cancer risk, although the mechanisms have yet to be detailed. This study aimed to elucidate promotion of pancreatic cancer by obesity and hyperlipidemia. Six-week-old female Syrian golden hamsters were treated with N-nitrosobis(2-oxopropyl)amine (BOP) and after 1 week were fed a high-fat diet (HFD) or standard diet (STD) for 6 or 17 weeks. Body weight and serum levels of lipids and leptin were significantly higher in the HFD than the STD group at 14 weeks of age. Pancreatic ductal adenocarcinomas developed only in the BOP + HFD group, with an incidence of 67% (P < 0.01) at 14 weeks of age. In addition, the multiplicity was 2-fold greater in the BOP + HFD group than in the BOP + STD group (P < 0.05) at 25 weeks of age. Pancreatic fatty infiltration was increased by BOP treatment and further enhanced by the HFD, correlating with progression of BOP-induced pancreatic ductal adenocarcinoma and up-regulated expression of adipocytokines and cell proliferation-related genes in the pancreas. High-fat diet is shown to increase serum lipid levels and enhance fatty infiltration in the pancreas with abnormal adipocytokine production, which may accelerate and enhance pancreatic cancer.

Flaxseed Reduces Tg, Apob And Lipoproten(a) In Model Of Postmenopausal Hypercholesterolemia

The prevalence of CVD dramatically increases with estrogen deficiency during menopause. Due to the side effects and low compliance of HRT, postmenopausal women seek natural alternative therapies. Flaxseed has been shown to inhibit atherosclerotic lesion formation however it is not known whether it can reverse formation that has already occurred. PURPOSE: The goal of this project was to understand the full clinical application of flaxseed in altering lipid/lipoprotein profiles. METHODS: For this study, 72 female Golden Syrian hamsters (3-month old) were randomly divided into 6 groups (n of 12) and either sham-operated (sham) or ovariectomized (ovx) and were kept on the same diet for 120 days to allow for atherosclerotic lesion development. Following this 120 day period whole flaxseed was introduced to the diets of the hamsters in three of the groups as follows: Group 1 (sham plus casein); Group 2 (ovx plus casein); Group 3 (ovx plus 7.5% flaxseed); Group 4 (ovx plus 15% flaxseed); Group 5 (ovx plus 22.5% flaxseed); and Group 6 (ovx plus 17-beta estradiol). This diet was maintained for an additional 120 days. Serum was analyzed for TC, TG, LDL-C, HDL-C, Apolipoproteins A and B and Lipoprotein (a). RESULTS: Results showed that 15 and 22.5% flaxseed, compared to ovx animals, significantly reduced Lipoprotein (a) [4.4 (ovx) vs. 2.15 mg/dL (15% flax) and 4.4 (ovx) vs. 0.3 (22.5% flax) mg/dL; P< 0.05] and Apo B [2.8 (ovx) vs. 2.4 mg/dL (15% flax) and 2.8 (ovx) vs. 2.5 mg/dL (22.5% flax). All flax treated animals had significantly lowered (P<0.05) TG levels compared to ovx animals [151.7 (ovx) vs. 110.4 (7.5% flax), 105.4 (15% flax) and 112.5 (22.5% flax). CONCLUSIONS: These results support the use of flaxseed to improve the lipid profile. Furthermore, Lipoprotein (a) is a strong risk factor for CVD so the decrease seen with flaxseed is encouraging and may require further investigation. Supported by: USDA National Research Initiative Postdoctoral Fellowship Grant #2008-01926

Flaxseed but Not Flaxseed Oil Prevented the Rise in Serum Cholesterol Due to Ovariectomy in the Golden Syrian Hamsters

This study was designed to investigate whether flaxseed oil (FO) exerts hypocholesterolemic effects similar to ground whole flaxseed (WF) and to gain insight into its hypocholesterolemic mechanism. Forty-eight 6-month-old female Golden Syrian hamsters were either sham-operated (Sham) or ovariectomized (Ovx) and randomly assigned to one of four treatment groups (n = 12/group) for 90 days: Sham, Ovx, Ovx+WF, or Ovx+FO. Hamsters in the Sham and Ovx groups were fed a semipurified diet (control), whereas Ovx+WF and Ovx+FO received the same basic diet supplemented with either WF (15% wt/wt) or FO (amount equivalent to the oil contribution of WF). Ovariectomy significantly (P < .05) increased serum total concentrations by approximately 15%. WF, but not FO, prevented (P < .05) the ovariectomy-induced increase in serum total cholesterol concentration (12% and 4% reduction by WF and FO, respectively). Hamsters fed FO or WF had high-density lipoprotein (HDL)-cholesterol concentrations similar to those of the Ovx hamsters receiving the control diet. Non-HDL-cholesterol concentrations were lowest in the WF group, albeit not statistically different from the other treatment groups. There were no significant differences among groups in serum triglyceride concentration and liver lipids. Both WF and FO more than doubled the hepatic protein levels of 7α-hydroxylase in comparison to the Ovx hamsters receiving the control diet (P < .05). Our findings suggest that increased bile acid synthesis is one of the major cholesterol-lowering mechanisms of flaxseed and that other flaxseed components, aside from its oil, contribute to its hypocholesterolemic property. The cholesterol-lowering effects of other components of flaxseed and their mechanisms of action need to be further explored.

Abstract 2478: Early and enhanced development of N-nitrosobis(2-oxopropyl)amine-induced hamster pancreatic adenocarcinomas by high-fat diet

Abstract Epidemiologically, obesity is associated with pancreatic cancer risk, but the mechanisms of obesity-associated carcinogenesis have not yet been clearly understood. Hypertrophic white adipose tissues secrete many adipokines and inflammatory factors, which are expected to enhance cancer development. Syrian golden hamsters, which are used in pancreatic carcinogenesis studies, are in a hyperlipidemic state even under normal diet conditions. We previously have shown that pioglitazone, a PPAR γ ligand, improves hyperlipidemia and suppresses N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic ductal carcinoma development. In the present study, effects of a high-fat diet (HFD) on hyperlipidemia and pancreatic carcinogenesis in BOP-treated hamsters were examined. Six-week-old female Syrian golden hamsters were subcutaneously injected with BOP (10 mg/kg body weight) four times in a week and from 8 weeks of age, the animals in the HFD groups were fed Quick Fat Diet (CLEA Japan, crude fat 14.3 %) for 6 or 17 weeks. At 14 weeks of age, serum levels of triglycerides, total cholesterol, free fatty acids and leptin were significantly elevated in hamsters fed the HFD, and pancreatic ductal adenocarcinomas were already observed in the BOP + HFD group. Pancreatic fatty infiltration was observed to increase in BOP-treated and HFD-fed hamsters. At 25 weeks of age, serum levels of total cholesterol and free fatty acids were further increased in each group and pancreatic ductal adenocarcinomas developed both in the BOP + standard diet group and BOP + HFD group. The numbers of dysplasia and adenocarcinomas in the pancreas were significantly higher in the BOP + HFD group than in the BOP + standard diet group. Apparent fatty infiltration was observed in relatively large adenocarcinomas in the BOP + HFD group. In conclusion, the HFD aggravated the hyperlipidemia, shortened the latency periods of cancer and increased numbers of BOP-induced pancreatic precancerous lesions and adenocarcinomas. Fatty infiltration was apparent in the pancreas of the HFD group and may be associated with pancreatic cancer development in hamsters. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2478.

Development and Characterization Of Cell Lines Derived From Hamster Breast Carcinomas As Model Of Oncolytic Virotherapy

Two models of breast cancer to study oncolytic virotherapy were investigated in female Syrian golden hamsters. In contrast to most other species examined, the Syrian hamster is permissive for human Adenovirus replication. Single doses of 2 carcinogens to 2 different groups of animals were administered: 7,12‐dimethylbenz[a]anthracene (DMBA) or N‐methylnitrosourea (MNU). Body weights, palpations and PET imaging for tumors were recorded. Animals were necropsied and tissues were taken for primary culture, histology and H&amp;E staining. After cell lines were established from primary tumors, karyotyping, infectivity, oncolytic activity, and growth rate were determined. Both lines contain 74 chromosomes where normal for hamster is 44. Histology determined the DMBA line was derived from a highly aggressive, poorly differentiated carcinoma. When injected into nude mice xenografts, the DMBA derived line grew rapidly, invaded into underlying muscle, and metastasized to lung and bone. The MNU line, clearly an adenocarcinoma, was syngeneicly transplanted into recipient hamsters with a take rate of &lt;50%; those tumors were harvested, grown in primary culture, and transplanted again with a take rate of 100%. The MNU line shows promising results for use in oncolytic virotherapy while the DMBA might prove to be useful in testing for failed drugs. Funding: Feist‐Weiller Cancer Center and the LA Gene Therapy Consortium

Protective action of taurine, given as a pretreatment or as a posttreatment, against endotoxin-induced acute lung inflammation in hamsters

To assess the effect of taurine on lipopolysaccharide (LPS)-induced lung inflammation, oxidative stress and apoptosis, female Golden Syrian hamsters were intratracheally instilled with bacterial LPS (0.02 mg in phosphate buffered saline (PBS) pH 7.4), before or after a 3-day intraperitoneal treatment with a single dose of taurine (50 mg/kg/day in PBS pH 7.4), and bronchoalveolar lavage fluid (BALF) and lung tissue samples were collected at 24 hr after the last treatment. In comparison to BALF samples from animals receiving only PBS pH 7.4, and serving as controls, those of LPS-stimulated animals exhibited a higher count of both total leukocytes and neutrophils and increased expression of tumor necrosis factor receptor 1. In comparison to lungs from control animals, those from LPS-treated animals showed increased cellular apoptosis, lipid peroxidation, decreased glutathione levels, altered activities of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and focal inflammation confined to the parenchyma. A treatment with taurine was found to significantly attenuate all these alterations, with the protection being, in all instances, greater when given before rather than after LPS. The present results suggest that taurine is endowed with antiinflammatory and antioxidant properties that are protective in the lung against the deleterious actions of Gram negative bacterial endotoxin.

P162 Use of naked DNA immunization for screening of leptospiral antigens as potential vaccinogens

The genomic DNA of Leptospira interrogans Canicola strain Kito was used as a template for amplification of the target sequences and vaccinogen production. Female Golden Syrian hamsters with 4 5 weeks of age were immunized according to previously described protocols: 80/40 μg (first/second immunization) or 80/40/40 μg (first/second/third immunization) for subunit vaccines and 100/100 mg for plasmid vectors. Each experimental group included 6 to 8 animals. Homologous challenge was tested by strain Kito and heterologous challenge by L. interrogans serovar Copenhageni strain Fiocruz L1-130.

Attenuating effect of taurine on lipopolysaccharide-induced acute lung injury in hamsters

This study has evaluated the ability of the semiessential amino acid taurine to attenuate lipopolysaccharide (LPS)-induced lung inflammation, oxidative stress and apoptosis in a small animal model. For this purpose, bacterial LPS (0.02 mg in phosphate buffered saline (PBS) pH 7.4) was instilled intratracheally into female Golden Syrian hamsters, before or after a 3-day intraperitoneal treatment with a single dose (50 mg/kg in PBS pH 7.4) of taurine. At 24 h after the last treatment, lung tissue and bronchoalveolar lavage fluid (BALF) samples were collected. In comparison to samples from animals receiving only PBS pH 7.4, serving as controls, those of LPS-stimulated animals exhibited a higher count of both total leukocytes and neutrophils in the BALF, and increased incidence of apoptosis, depletion of intracellular glutathione and evidence of inflammation confined to the parenchyma in the lung. In addition, LPS caused cells in the BALF to exhibit a higher expression of tumor necrosis factor-1, a higher activity of caspase-3, marked lipid peroxidation, and altered activities of catalase, glutathione peroxidase and superoxide dismutase relative to control samples. In contrast, a treatment with taurine was found to significantly attenuate all of the cellular and biochemical alterations induced by LPS, more so when given before rather than after the endotoxin. The present results suggest that taurine possesses intrinsic antiinflammatory and antioxidant properties that may be of benefit against the deleterious actions of LPS in the lung.

Biotransformation of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone in Lung Tissue from Mouse, Rat, Hamster, and Man

Exposure to the tobacco-specific N-nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is considered to be an important etiological risk factor for lung cancer in tobacco users. The metabolism of NNK via carbonyl reduction to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), alpha-hydroxylation to form both DNA methylating and pyridyloxobutylating intermediates, and detoxification by pyridyl N-oxidation and glucuronide formation are well-characterized in laboratory animals but less so in man. The in vitro kinetics of 0.03-250 microM [5-(3)H]NNK metabolism were determined under identical experimental conditions using female A/J mouse, male Fischer 344 rat, female Syrian golden hamster, and human lung tissue explants in tissue culture. The concentration-dependent percentage contribution of the three major pathways of NNK metabolism (carbonyl reduction, alpha-hydroxylation, and N-oxidation) showed large interspecies variation. Quantitatively, in mouse, carbonyl reduction to NNAL increased steadily with an increasing substrate concentration (10-74% total NNK metabolism), while concurrent decreases occurred in end products of alpha-hydroxylation (60 to 18%) and N-oxidation (42 to 5%). In rat lung, there were no apparent concentration-dependent trends (NNAL, 42 +/- 4%; alpha-hydroxylation, 35 +/- 2%; and N-oxidation, 24 +/- 3%). In hamster lung, a clear concentration-dependent increase in the contribution of NNAL to total NNK metabolism (from 47 to 87%) was paralleled by a steady decline in end products of alpha-hydroxylation (31 to 11%) and N-oxidation (22 to 2%). Human lung metabolism showed no concentration-dependent tendencies (NNAL, 89 +/- 1%; alpha-hydroxylation, 8.8 +/- 1.1%; and N-oxidation, 2.1 +/- 0.3%). The major alpha-hydroxylation product in human lung was 4-hydroxy-1-(3-pyridyl)-1-butanone (keto alcohol), thus supporting the potential pyridyloxobutylation of lung DNA. Metabolism to 4-(3-pyridyl)-4-oxobutanoic acid (keto acid), which could result in lung DNA methylation, was only sporadically seen in human lung but present to a far greater extent in rodent lung. No evidence for glucuronidation was found in any species. Generally, the rate of formation of all NNK metabolites showed two different enzyme kinetics, resulting in large differences between apparent K(m) and V(max) values in the low (up to 2.8 microM) and high substrate concentration ranges. The metabolism of NNK by alpha-hydroxylation is considerably lower in human lung as compared to that observed in rodent species, suggesting that extrapolation of in vitro rodent data to man may result in invalid conclusions about the capacity of the human lung to activate NNK under realistic conditions of NNK exposure expected to occur in man.

Effects of bedding material and running wheel surface on paw wounds in male and female Syrian hamsters

The present study investigated the effects of bedding material (pine shavings versus beta chip) and running wheel surfaces (standard metal bars versus metal bars covered with a plastic mesh) on the occurrence of wounds on the paws of male and female Syrian (golden) hamsters, Mesocricetus auratus. Four groups of 10 males and 10 females were each assigned to one of the following treatments: pine/no mesh, pine/mesh, chips/no mesh and chips/mesh. Each hamster paw was observed at 1-3-day intervals for 60 days. A total of 1-3 wounds, separate in time, developed on the paws (mostly the hind ones) of almost all animals. Wounds appeared as small pinpricks, cuts or scabs, mostly on the palms. Females ran 15% less than males, yet their front paws were more commonly affected and their wounds tended to last longer. Hamsters with plastic mesh inside their wheels took longer to develop wounds but once they appeared, the wounds were larger and lasted longer. Hamsters on pine shavings developed fewer wounds and had more wound-free days. Hamsters kept running at high levels and many wounds did not heal during the study, suggesting a need for veterinary intervention.

Infrequent Mutation of Lysophosphatidic Acid Receptor-1 Gene in Hamster Pancreatic Duct Adenocarcinomas and Established Cell Lines

To evaluate the involvement of lysophosphatidic acid receptor-1 (LPA1) gene alteration in pancreatic carcinogenesis, we investigated mutations in the LPA1 gene in hamster pancreatic duct adenocarcinomas (PDAs) and established cell lines. Female Syrian golden hamsters received 30 mg/kg of N-nitrosobis(2-oxopropyl)amine (BOP) followed by repeated exposure to an augmentation pressure regimen consisting of a choline-deficient diet combined with DL-ethionine and then L-methionine and a further administration of 20 mg/kg BOP. A total of 10 PDAs obtained 10 weeks after beginning the experiment and three cell lines established from subcutaneously transplantable PDAs in syngeneic hamsters were examined for mutations using reverse transcription-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) analysis. A mutation was detected in only one PDA (1/10, 10%) in the form of a GGA to GTA (Gly to Val) transversion at codon 355, and no mutations were detected in the three cell lines. These results suggest that the LPA1 gene mutation may play roles in a limited fraction of BOP-induced pancreatic duct carcinogenesis in hamsters.