A reliable externally fixated murine femoral fracture model that accounts for variation in movement between animals.

Fifty-two CFLP mice had an open femoral diaphyseal osteotomy held in compression by a four-pin external fixator. The movement of 34 of the mice in their cages was quantified before and after operation, until sacrifice at 4, 8, 16 or 24 days. Thirty-three specimens underwent histomorphometric analysis and 19 specimens underwent torsional stiffness measurement. The expected combination of intramembranous and endochondral bone formation was observed, and the model was shown to be reliable in that variation in the histological parameters of healing was small between animals at the same time point, compared to the variation between time-points. There was surprisingly large individual variation in the amount of animal movement about the cage, which correlated with both histomorphometric and mechanical measures of healing. Animals that moved more had larger external calluses containing more cartilage and demonstrated lower torsional stiffness at the same time point. Assuming that movement of the whole animal predicts, at least to some extent, movement at the fracture site, this correlation is what would be expected in a model that involves similar processes to those in human fracture healing. Models such as this, employed to determine the effect of experimental interventions, will yield more information if the natural variation in animal motion is measured and included in the analysis.

Severe Vitamin E deficiency modulates airway allergic inflammatory responses in the murine asthma model

Allergic asthma is a complex immunologically mediated disease associated with increased oxidative stress and altered antioxidant defenses. It was hypothesized that a-tocopherol (a-T) decreases oxidative stress and therefore its absence may influence allergic inflammatory process, a pathobiology known to be accompanied by oxidative stress. Therefore, selected parameters of allergic asthma sensitization and inflammation were evaluated following ovalbumin sensitization and re-challenge of a-T transfer protein (TTP) knock-out mice (TTP-/-) that have greatly reduced lung a-T levels (e.g.

Quantification of Hox and Surfactant Protein-B Transcription during Murine Lung Development.

Abstract BACKGROUND: Genetic processes underlying fetal lung development and maturation are incompletely understood. Better knowledge of these processes would provide insights into the causes of lung malformations and prevention of respiratory distress syndrome and the potential adverse effects of glucocorticoids. Hox genes are involved in the lung branching morphogenesis and maturation of respiratory epithelium, but their expression pattern remains to be defined. OBJECTIVES: We hypothesized that genes involved in lung branching would be downregulated during early development, whereas those involved in maturation would be unchanged or upregulated. METHODS: TaqMan real-time primers and probes were designed for all 39 murine Hox genes, and the murine SP-B gene and transcription profiles of these genes were obtained from whole lungs isolated at e14.5, e16.5, e18.5, e19.5 and postnatal days 1 and 20. RESULTS: Hox genes in clusters A and B, specifically those between paralog groups 3 and 7, were the most represented, with Hoxa4 and Hoxa5 being the most highly transcribed. A wave of reduced transcription in 16 Hox genes, coincident with increased SP-B transcription, was observed with advancing gestation. Consistently high transcription of Hoxa5 from e14.5 to postnatal day 20 may indicate that sustained transcription is required for normal lung maturation. When e15.5 lungs were cultured with dexamethasone, Hoxb6, Hoxb7 and Hoxb8 levels were significantly upregulated, creating the potential for modulation of diverse downstream target genes. CONCLUSIONS: Improved understanding of the genetic processes underlying lung development afforded by our Q-PCR platform may allow development of more specific methods for inducing fetal lung maturation.