Tocolytic Effects of Meloxicam on Isolated Cattle Myometrium

Abstract

Meloxicam is a selective, cyclooxygenase-2 (COX-2), enzyme inhibiting, non-steroid, and anti-inflammatory drug (NSAID). In this study, its tocolytic effects on the cattle myometrium strips pre-stimulated with oxytocin (OT) were investigated with the isolated tissue bath system. The uterine samples were from newly slaughtered, non-pregnant cattle which were older than two years old and in anoestrus stage at the time of sampling, in a registered slaughterhouse. Seven cattle samples (each sample consisted of four strips) were used in this study. The samples were incubated in the isolated tissue baths until regular spontaneous contractions occurred. 0.5 nM of OT was then applied to all strips. After OT application, 10 different doses of meloxicam (sodium salt) ranging between 1x10(-7) and 7x10(-4) M were administered, cumulatively. After each application, uterine contractions were recorded for 20 min. Mean peak amplitude (peak maximum, PMAX), frequency (beats per minute, BPM) and area under the curve (AUC) values of the uterine contractions, which were used to evaluate the effects of the drug, were calculated from the curve. In addition, the effective concentration 50 (EC50) values for the tocolytic effects of meloxicam were calculated 4.22x10(-4) M (2.63-6.76x10(-4) M, 95% confidence limits for mean, CLM) for frequency (BPM), 3.61x10(-4) M (2.47-5.27x10(-4) M, 95% CLM) for AUC and 2.31x10(-4) M (1.97-2.70x10(-4) M, 95% CLM) for peak amplitude (PMAX), by using the GraphPad Prism (5.0) program. At the end of this study, it is suggested that the use of meloxicam as a tocolytic agent may prevent preterm labour in cattle and the loss of calves. However, in vivo studies should be performed to show the clinical therapeutic and possible maternal and foetal adverse effects of meloxicam on live cattle.