Bronchoconstrictive properties of inhaled 8-epi-PGF2alpha in healthy and heaves-susceptible horses.

This research article investigates the impact of a molecule generated during Oxidative stress, 8-epi-PGF2alpha, on lung constriction in healthy and a type of asthma suffering horses referred to as heaves-susceptible horses. The study establishes that the inhalation of 8-epi-PGF2alpha may not cause bronchoconstriction in healthy horses, however, it may lead to minor bronchoconstriction in heaves-susceptible horses, albeit less than what is initiated by other agents like PGF2alpha and U46619.

Research Purpose and Hypothesis

• The researchers of the article hypothesized that the inhaled molecule 8-epi-PGF2alpha, a sign of Oxidative stress often found abundantly in lungs of humans and horses suffering from asthma, triggers bronchoconstriction (narrowing of the airways) in both healthy and heaves-susceptible horses. Heaves is a type of asthma that horses suffer from.

Methodology

• The study compared the impact of nebulised 8-epi-PGF2alpha on lung behavior to that of PGF2alpha and U46619, which are known to cause bronchoconstriction, in both healthy and heaves-susceptible horses when they’re in clinical remission.
• They used six healthy horses and six heaves-susceptible horses for this evaluation. For each horse, they measured the pulmonary resistance (R(L)) and dynamic compliance (Cdyn) before and after inhalation of 1 mg 8-epi-PGF2alpha, PGF2alpha, U46619, and placebo.

Findings

• The study found that the inhalation of 8-epi-PGF2alpha did not change R(L) or Cdyn in healthy horses, implying that it does not cause bronchoconstriction in healthy horses.
• In contrast, in heaves-susceptible horses, inhalation of 8-epi-PGF2alpha led to a significant increase in R(L) and a significant decrease in Cdyn compared to the baseline. It indicates that 8-epi-PGF2alpha can lead to mild bronchoconstriction in heaves-susceptible horses.
• However, the difference in R(L) and Cdyn values after 8-epi-PGF2alpha inhalation and those of placebo inhalation were not significant, indirectly suggesting the impact of 8-epi-PGF2alpha itself might not be substantial.
• Furthermore, PGF2alpha and U46619 induced significant bronchoconstriction in both healthy and heaves-susceptible horses, with the R(L) increase being notably higher in the asthma-suffering horses than in healthy ones after inhalation of PGF2alpha, showing that these substances have a stronger impact than 8-epi-PGF2alpha.

Conclusion

• Overall, the study concludes that while 8-epi-PGF2alpha may cause mild bronchoconstriction in heaves-susceptible horses, it does not have the same effect on healthy horses. Additionally, its bronchoconstrictive effect in heaves-susceptible horses seems far less efficient than that caused by PGF2alpha and U46619 at the same dose.