Transcriptional changes associated with recurrent airway obstruction in affected and unaffected horses.

This study investigates the gene differences in lung tissues of horses suffering from a form of recurrent airway obstruction (RAO) compared to healthy horses. The researchers identified 18 differentially expressed genes (17 upregulated and 1 downregulated) associated with the disease.

Research Objectives and Methods

• The primary objective of the study was to track changes in the expression levels of genes in the lung tissues of horses affected by Summer Pasture-Associated Obstructive Pulmonary Disease (SPAOPD-RAO), a form of Recurrent Airway Obstruction (RAO).
• Research was conducted on six horses with SPAOPD-RAO and six healthy horses as the control group. The grouping was based on medical history, clinical score, and transpleural pressure – a measure of the pressure difference across the lungs.
• Total RNA was extracted from the five lung lobes of each affected horse, pooled together, and compared with RNA pooled from unaffected horses.
• Researchers used Differential Display (DD) polymerase chain reaction (PCR) assay – a technique used in biochemistry to amplify selected portions of the DNA or RNA for further analysis.
• Expressed bands showing differences were purified and cloned into plasmid vectors to create multiple copies of the DNA sequence. These were then sequenced for analysis.

Findings

• The results showed a difference in the expression of 18 genes, where 17 were upregulated (increased expression) and one was downregulated (decreased expression) in the SPAOPD-RAO affected horses as per DD-PCR assay findings.
• Three genes, in particular, showed significant expression alterations (two upregulated and one downregulated) and were re-confirmed using Real-Time PCR, a technique to measure the actual amplification of the DNA.

Conclusion

• This research suggests that SPAOPD-RAO is a complex disease in horses that involves alterations in the expression of multiple genes.
• Notably, the upregulated beta2-microglobulin gene and the downregulated secretoglobin gene identified in this study could potentially serve as marker genes for detecting SPAOPD-RAO in horses at an early age.