Endothelin-1 (ET-1) has been implicated in allergic type of respiratory inflammatory diseases in various species of animals including horses. This peptide elicits its actions by acting through endothelin-A (ET-A) and endothelin-B (ET-B) receptor sub-types. In this project, we have hypothesized that endothelin receptors (both ET-A and ET-B) are altered in terms of affinity and expression, in the lungs of summer pasture-associated obstructive pulmonary disease (SPAOPD)-affected horses. Objective of this dissertation was to determine the alterations in the affinity and expression of endothelin receptors in the lungs of healthy and SPAOPD-affected horses. To pursue our hypothesis, we have employed pharmacological, immunohistochemical and molecular studies. Totally 33 horses were used in this study. All the horses were examined and grouped in to 16 healthy and 17 SPAOPD-affected, based on clinical evaluation, clinical scoring, pulmonary function testing and broncho-alveolar lavage fluid (BALF) analysis. Horses were then euthanatized, and tissue specimens were immediately collected from all lung lobes. In pharmacological studies, cumulative concentration response curves and pA2 values were determined and compared in both groups of horses. The pA2 value of ET-B receptors was significantly greater in the SPAOPD-affected horses when compared with healthy horses. In immunohistochemical studies, expression of these receptors was determined in the bronchial smooth muscles and epithelium of both groups of horses. The percentage of immunostaining was significantly greater in the smooth muscles of SPAOPD-affected horses when compared with healthy horses. In molecular studies, by employing RT-PCR, western blotting and realtime PCR, expression of these receptors has been determined and compared. The molecular expression of ET-B receptors was siginifcantly greater in the peripheral lungs of SPAOPD-affected horses when compared with healthy horses. Specific antagonists, primers and polyclonal primary antibodies of ET-A or ET-B receptors were used for these three studies. On the whole, it can be concluded that ET-B receptors show a clear tendency of up-regulation in the lungs of SPAOPD-affected horses. These findings help us in the better understanding of the pathogenesis of this progressive, career-ending disease.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-03102006-234119 |
| Date | 15 March 2006 |
| Creators | Polikepahad, Sumanth |
| Contributors | Changaram S. Venugopal, Rustin M.Moore, Joseph Francis, Daniel B.Paulsen, Steven Barker, Michael Welsch |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-03102006-234119/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.007 seconds