No gender difference in development of obliterative airway disease in rat tracheal allografts

Low-molecular-weight heparins do not modify obliterative airway disease in rat tracheal allografts

Immunosuppressive and antiproliferative effects of heparin may be beneficial in the field of solid organ transplantation. The aim of this study was to examine the effect of low-molecular-weight heparin (LMWH) compounds on the development of obliterative airway disease (OAD) in the rat tracheal transplant model. Allogenic heterotopic tracheal transplantations were performed from Brown-Norway into Lewis rats. Recipients were treated either with nadroparin, enoxaparin, parnaparin, or vehicle from day 0 until harvesting at day 7 or 21. Graft rejection was morphometrically assessed to determine the extent of luminal obliteration end epithelial necrosis. All tracheal grafts harvested at day 7 demonstrated nearly equivalent degree of luminal obstruction regardless of treatment regimen. Likewise, at day 21 the extent of airway narrowing and the degree of inflammatory cell infiltration were similar among the groups. Moreover, loss of airway epithelium was not prevented by LMWH treatments. Finally, intragraft mRNA expression for transforming growth factor-β1 and platelet-derived growth factor-A, interleukin-2, interferon-γ, and monocyte chemoattractant protein-1 did not differ between the groups. In contrast with findings in other animal models, treatment with LMWH preparations did not modify the development of OAD in rat tracheal allografts.

Late treatment with angiotensin-converting enzyme inhibitors plus endothelin receptor antagonists ameliorates rat tracheal allograft rejection

Inhibition of the renin-angiotensin and endothelin (ET) systems prevents the development of obliterative airway disease (OAD) in rat tracheal allografts. In this study, we assessed whether these therapeutic approaches are effective even when the same were started after signs of OAD were already manifest. Rat tracheas were heterotopically transplanted from Brown-Norway donors into Brown-Norway or Lewis recipients. Allograft recipients received bosentan, ramipril, bosentan plus ramipril or vehicle from day 10 to 24. Untreated allografts and isografts were harvested at day 10 or 24. In tracheal grafts, morphometric studies together with molecular analysis by real-time PCR were performed. Fibroproliferative process in untreated tracheal allografts but not in isografts started already at day 10. Neither bosentan nor ramipril treatment alone as monotherapy could modify the development of OAD when administered only between day 10 and day 24. By contrast, the combination treatment of bosentan and ramipril ameliorated airway obstruction by day 24, which was accompanied by reduced mRNA expression of intragraft transforming growth factor-beta1 and platelet-derived growth factor-A and -B chains. Only the combined blockade with angiotensin-converting enzyme inhibitors and ET receptor antagonists can reduce the progression of OAD in this model if the treatment is initiated late in the disease course.

Basal gene expression in male and female Sprague-Dawley rat nasal respiratory and olfactory epithelium

The nasal epithelium is an important target site for chemically induced toxicity and carcinogenicity. Experimental studies show that site-specific lesions can arise within the nasal respiratory or olfactory epithelium following the inhalation of certain chemicals. Moreover, gender differences in epithelial response are also reported. To better understand and predict gender differences in response of the nasal epithelium to inhaled xenobiotics, gene expression profiles from naive male and female Sprague-Dawley rats were constructed. Epithelial cells were manually collected from the nasal septum, naso- and maxillo-turbinates, and ethmoid turbinates of nine male and nine female rats. Gene expression analysis was performed using the Affymetrix Rat Genome 430 2.0 microarray. Surprisingly, there were few gender differences in gene expression. Gene ontology enrichment analysis identified several functional categories, including xenobiotic metabolism, cell cycle, apoptosis, and ion channel/transport, with significantly different expression between tissue types. These baseline data will contribute to our understanding of the normal physiology and selectivity of the nasal epithelial cells' response to inhaled environmental toxicants.