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Elaine Por, Melody Sandoval, Chiquita Thomas-Benson, Teresa A Burke, Brian Lund; Repeated low- level blast exposure increases transient receptor potential vanilloid 1 (TRPV1) and endothelin-A (ET-A) co-expression. Invest. Ophthalmol. Vis. Sci. 2017;58(8):216. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Blast injuries are generally categorized as primary to quaternary and can evoke a myriad of effects on multiple body systems. Importantly, ocular injuries are the fourth most common battlefield injury, constituting approximately 13% of all combat injuries. Despite extensive research focused on the effects of blast on neurosensory function, limited data are available on the effects on pain and inflammatory processes. Recent studies conducted in our laboratory have revealed increased expression of transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1), critical mediators involved in pain transmission, in rat corneas following single and repeated low-level blast exposure. These data indicate that TRPV1 and ET-1 may contribute to the complex pathophysiology of blast-related injuries. The overall purpose of this study was to characterize the expression of both ET-1 receptor subtypes, endothelin-A (ET-A) and endothelin-B (ET-B), in blast-exposed ocular tissues.
A compressed air shock tube (Applied Research Associates, ARA) was used to deliver a single or repeated low-level blast (68.0 ± 2.7 kPa) to anesthetized rats once or daily for five consecutive days, respectively. Immunohistochemistry analysis was performed on ocular tissues collected at the conclusion of the experiments to determine co-expression of TRPV1, ET-A or ET-B following single and repeated blast exposure.
Increased expression of TRPV1 was observed in the rat cornea epithelial and stromal layers following exposure to both single and repeated low-level blast. Increased expression of ET-A was also detected in rat corneas as compared to control animals. Importantly, substantial co-expression of TRPV1 and ET-A was observed in rat corneas exposed to repeated low-level blast. Although modest increases in ET-B expression were observed following low-level blast exposure, these increases were unremarkable compared to ET-A.
Single and repeated low-level blast exposure resulted in increased co-expression of TRPV1 and ET-A in the rat cornea as compared to control. These findings provide additional insight into pain signaling pathways activated following blast exposure. Further studies are required to determine if blast-related ocular injuries leads to crosstalk of these receptor systems and the potentiation of pain and inflammatory processes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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