Effects of leukotriene C4 on the bioelectric properties and ion transport of equine tracheal epithelium.

This research explores the effects of leukotriene C4 (LTC4) on the ion transport across the tracheal epithelium of horses, underscoring aspects like chloride secretion and sodium absorption. Furthermore, the study inspects the role of LTC4 in possibly contributing to airway hypersecretion.

Methods

• The researchers utilized tracheal epithelium obtained from 24 horse cadavers, which were free of respiratory tract diseases.
• The tissue samples were installed in Ussing chambers, which are used for studying the transport of ions and drugs across biological membranes, and the short-circuit current was monitored.
• The impact of LTC4 was examined under various conditions such as the addition of specific chemicals (amiloride, bumetanide, barium) to the bathing solutions, and the replacement of certain ions like chloride with gluconate, and bicarbonate with HEPES.
• The transport of electrolytes was evaluated through (22)Na and (36)Cl isotope fluxes.

Results

• Introduction of LTC4 to the bath solution resulted in an increase in short-circuit current for basal conditions. This increment was larger after the treatment of tissue with amiloride.
• The observed increase was partly reversed by introducing bumetanide and further reduced by the replacement of bicarbonate with HEPES. The remaining current, thereafter, was decreased to amounts lesser than prior LTC4 treatment via the addition of barium.
• A small increase in short-circuit current was noted after amiloride addition and replacement of chloride with gluconate.
• Radioisotope flux revealed that the introduction of LTC4 boosted chloride secretion while curbing sodium absorption.

Conclusions

• LTC4 was found to stimulate chloride secretion primarily through a bumetanide-sensitive pathway, with a lesser contribution via a bicarbonate-dependent pathway.
• The study concludes that LTC4 might be a potential driving factor of airway hypersecretion in horses.