Differential effects of isoflurane and CO2 inhalation on plasma levels of inflammatory markers associated with collagen-induced arthritis in DBA mice

The Anti-Inflammatory Drug Aspirin Does Not Protect Against Chemotherapy-Induced Memory Impairment by Paclitaxel in Mice

Inflammation has been proposed to play a causal role in chemobrain which—if true—would represent an opportunity to repurpose existing anti-inflammatory drugs for the prevention and treatment of chemobrain. Here, we show that the chemoagent paclitaxel induces memory impairment and anhedonia in mice within 24 h of treatment cessation, but inflammation is not present until 2 weeks after treatment. We find no evidence of brain inflammation as measured by cytokine analysis at any time point. Furthermore, treating with aspirin to block inflammation did not affect paclitaxel-induced memory impairment. These findings suggest that inflammation may not be responsible for memory impairment induced by paclitaxel. These results contrast with recent findings of a causal role for inflammation in cancer-induced memory deficits in mice that were prevented by treatment with oral aspirin, suggesting that cognitive impairment in cancer patients undergoing treatment may arise from multiple convergent mechanisms.

Volatile Anesthetics and Immunity

Historically, volatile anesthetics have demonstrated interesting interactions with both the innate and adaptive immune systems. This review organizes these interactions into four phases: recognition, recruitment, response, and resolution. These phases represent a range of proinflammatory, inflammatory, and innate and adaptive immune regulatory responses. The interaction between volatile anesthetics and the immune system is discussed in the context of pathogenesis of infectious disease.

Deciphering Sources of Variability in Clinical Pathology-It's Not Just about the Numbers

Preanalytical variables can have significant impacts on clinical pathology parameters evaluated during the conduct of a nonclinical safety or toxicity study. These preanalytical variables can be controlled by careful attention to factors such as animal dietary status (diet composition, fasted, and fed state), restraint and anesthesia, intercurrent procedures, timing of clinical pathology collections, and proficiency of animal technicians. The impact of preanalytical variables on test results can be significant enough to result in difficult interpretations and/or regulatory questions or can obfuscate the effects of a test article. Control of preanalytical variables starts with knowledge of what processes and procedures impact test results. Minimizing these effects improves the quality of results and maximizes the value of the study.

In Utero exposure to genistein enhanced intranasal house dust mite allergen-induced respiratory sensitization in young adult B6C3F1 mice

Despite many hypothesized benefits of dietary isoflavone genistein (GEN) deriving from soy-based products, questions surrounding GEN's developmental immunotoxic effects are increasing. To understand how in utero GEN exposure may modulate postnatal respiratory sensitization, we conducted a time course study using a common household allergen (house dust mites: HDM; 10μg/mouse) following intranasal instillation, a physiological route of allergen exposure. GEN was administered to dams by gavage from gestational day 14 to parturition at a physiologically relevant dose (20mg/kg bw). Female and male offspring were sensitized with HDM allergens beginning about one month prior to sacrifice followed by challenges with three weekly doses of HDM extracts, and they were euthanized at day 3 following the final HDM exposure at four different time points (postnatal day (PND) 80, 120, 160, and 200). In utero GEN combined with postnatal HDM exposures (GEN+HDM) increased total IgE production in both young female and male B6C3F1 offspring (e.g., PND 80 in females and PND 120 in males). Increased antigen-specific IgG1, IgG2a and IgG2b levels were also observed at various time points in both female and male offspring. In addition, increases in macrophage number in bronchoalveolar lavage fluid of both female and male GEN+HDM offspring at PND 80 and PND 120, respectively, were observed when compared to the vehicle group. For T cells, an increase over the vehicle in female GEN+HDM offspring was observed at PND 80. Due to similar patterns of increases, it seems likely that GEN+HDM-induced increases in total IgE and macrophages are related. Overall, in utero GEN plus later-life HDM exposures exert increases in total IgE and HDM-specific IgG production as well as macrophage recruitments to the lung in young adult mice.

Evaluating methods of mouse euthanasia on the oocyte quality: cervical dislocation versus isoflurane inhalation

Cervical dislocation is a commonly used method of mouse euthanasia. Euthanasia by isoflurane inhalation is an alternative method which allows the sacrifice of several mice at the same time with an anaesthesia, in the aim to decrease pain and animal distress. The objective of our study was to assess the impact of these two methods of euthanasia on the quality of mouse oocytes. By administering gonadotropins, we induced a superovulation in CD1 female mice. Mice were randomly assigned to euthanasia with cervical dislocation and isoflurane inhalation. Oviducts were collected and excised to retrieve metaphase II oocytes. After microscopic examination, oocytes were classified into three groups: intact, fragmented/cleaved and atretic. Intact metaphase II oocytes were employed for biomedical research. A total of 1442 oocytes in the cervical dislocation group were compared with 1230 oocytes in the isoflurane group. In the cervical dislocation group, 93.1% of the oocytes were intact, versus 65.8% in the isoflurane group ( P ≤ 0.001). In light of these results, we conclude that cervical dislocation is the best method of mouse euthanasia for obtaining intact oocytes for biomedical research.

Murine models of H. pylori-induced gastritis and gastric adenocarcinoma

Laboratory mice have become one of the best animal species for mechanistic studies in gastrointestinal research. Their abundant genetic information, the way of causing carcinogenesis easily by transgenic and gene knockout techniques, limited effort in time and costs, and their practicability provide advantages over other animal models. Meanwhile, several murine practical models have been established for the investigation of the initiation, expansion, and progression of gastritis and gastric carcinoma, for assessing the effects of bacterial, genetic and environmental factors, and for evaluating therapeutic and preventive strategies in gastric diseases. This article gives a review of murine models of gastritis and gastric cancer, placing emphasis on the models associated with Helicobacter pylori infection and techniques used in our laboratory. We discuss matters of murine gastric anatomy, as well as techniques of infection, tissue preparation, and histology.

Comparison of hypothalamic mRNA levels in mice euthanized by CO₂ inhalation and focused-beam microwave irradiation

Focused-beam microwave irradiation (FBMI) is a relatively new method for euthanasia of small mammals and is available to most researchers. Compared with CO₂ inhalation, this method of euthanasia has the advantage of preserving fast-degrading metabolites. But differences in brain RNA quantity and quality, gene expression and histology in mice euthanized by CO₂ inhalation versus FBMI have not been investigated. Here the authors report that a smaller quantity of RNA was isolated from brains of mice euthanized by FBMI compared with those of mice euthanized by CO₂ inhalation. They also found relative differences in the levels of the expression of some genes. These studies suggest that either method can be used for histological analysis or RNA isolation, but the authors caution against combining the techniques within a single study on gene expression.

Differential effects of shiitake- and white button mushroom-supplemented diets on hepatic steatosis in C57BL/6 mice

Shiitake mushrooms (SMs) have been used in Asia for treatment and/or prevention of chronic diseases and hypercholesterolemia. Previously, we observed a diet supplemented with 5% SM resulted in a twofold increase in plasma IL-6 levels in DBA arthritic mice. An elevation in plasma IL-6 has also been implicated in the pathogenesis fatty liver disease. Thus, the aim of this study was to investigate the effect of SM supplemented-diet on hepatic steatosis. In study 1, eight-week old female C57BL/6 mice were randomly assigned to the following groups for 6 weeks: the AIN-93 diet; 5% SM, and 5% white button mushroom (WBM) supplemented diets (12/group). In study 2, mice were fed either the AIN-93 diet or SM (20/group). After 6 weeks, 13 mice fed SM diet were given the AIN93 diet for 8 or 15 days. Unlike other groups, all mice fed the SM diet developed fatty liver (mean histopathology score 4.5 vs <1 in the other groups; p<0.001) without fibrosis and inflammation. Fifteen days post withdrawal of SM completely normalized liver histology. To the best of our knowledge, this is the first report that chronic consumption of SM is associated with the development of fatty liver. The mechanism by which SM causes hepatic steatosis warrants further investigation.

White button and shiitake mushrooms reduce the incidence and severity of collagen-induced arthritis in dilute brown non-agouti mice

Exotic mushrooms have been used in ancient Chinese medicine due to their immunomodulatory properties for the treatment and/or prevention of chronic diseases. However, only limited data exist on the health benefits of white button mushrooms (WBM), the most common in the American diet. In the current study, we investigated the effects of WBM and shiitake mushrooms (SM) on collagen-induced arthritis (CIA) using a 2 x 3 factorial design in 8-wk-old female dilute brown non-agouti mice that were fed a control diet (n = 37) or the same diet supplemented with 5% lyophilized WBM or SM (n = 27) for 6 wk. CIA was induced by immunizing mice with 100 µg bovine collagen followed by 50 µg LPS on d 20 post-collagen injection. CIA was assessed by mononuclear cell infiltration, bone erosion, plasma IL-6, TNFα, and intercellular adhesion molecule-1 (sICAM-1) concentrations. Compared with the control diet, WBM and SM tended to reduce the CIA index from 5.11 ± 0.82 to 3.15 ± 0.95 (P = 0.06) (median, 6-9 to 1-2) 31 d post-collagen injection. Whereas 58% of control mice had a CIA index ≥ 7, only 23% of WBM and 29% of SM mice did (P = 0.1). Although both types of mushrooms reduced plasma TNFα (34%, WBM; 64%, SM), only SM increased plasma IL-6 by 1.3-fold (P < 0.05). The CIA index was positively correlated with sICAM1 (r = 0.55; P < 0.05) but negatively correlated with TNFα (r = 0.34; P < 0.05). Whether mushrooms are beneficial for arthritis management remains to be investigated. To our knowledge, this is the first report demonstrating a possible health benefit of WBM in arthritis treatment.