The International Journal of Developmental Biology

Int. J. Dev. Biol. 66: 373 - 381 (2022)

Cyclooxygenase-2 plays a crucial role during myocardial patterning of developing chick

Bhaval K. Parmar, Urja R. Verma, Juhi A. Vaishnav, Suresh Balakrishnan*

Department of Zoology, Faculty of Science, The Maharaja Sayajirao University of Baroda Gujarat, India


Cyclooxygenase-2 (COX-2), a member of the Cyclooxygenase family, initiates the biosynthesis of prostanoids that regulates various cellular functions. Our pilot attempt revealed that the administration of etoricoxib, an inhibitor specific for COX-2, induces abnormal looping in the chicken heart. The present study attempts to reveal the mechanistic details of etoricoxib-induced abnormal cardiac looping. The activity of COX-2 was inhibited by administering 3.5 μg of etoricoxib into the egg’s air cell on day zero of incubation. The gene and protein expression patterns of key mediators of heart development were then analyzed on day 2 (HH12) and day 3 (HH20). Reduced COX-2 activity altered the expressions of upstream regulators of organogenesis like Wnt11, BMP4, and SHH in the etoricoxib-exposed embryos. The observed expression shifts in the downstream regulators of myocardial patterning (MYOCD, HAND2, GATA4, GATA5, and GATA6) in the treated embryos corroborate the above results. In addition, the reduction in COX-2 activity hampered cardiomyocyte proliferation with a concomitant increase in the apoptosis rate. In conclusion, the collective effect of altered expression of signaling molecules of myocardial patterning and compromised cardiomyocyte turnover rate could be the reason behind the looping defects observed in the heart of etoricoxib-treated chick embryos.


chick embryo, heart development, cyclooxygenase-2, looping, trabeculation

This article requires institutional access

Your institutional access has not been identified. Please log in