Effects of Ceftiofur and Meloxicam on conctractions of uterine isolated from non-pregnant cows

This study investigated the effects of third-generation cephalosporin ceftiofur and meloxicam on spontaneous contractility of the myometrium isolated from non-pregnant cow and heifer uterus.Myometrial strips were isolated from cows and heifers in follicular phase and suspended in a 5-ml jacketed organ bath filled with Krebs solution at 38?C (pH 7.4) continuously bubbled with 95% oxygen and 5% carbon dioxide. After manifestation of the spontaneous contractions during equilibration period of 90 minutes, isometric contractions were recorded by using isometric force displacement transducer and initial 10 minute was considered as control period. Than, the test substances ceftiofur (500 µM, cumulative 1000 µM and 2000 µM, n=16) and meloxicam (0.5 µM, cumulative 1.0 µM and 2.0 µM, n=17) were added to the tissue bath and evaluated by 10-min intervals. The effects of ceftiofur and meloxicam on amplitude (mg), frequency and area under the contractile curve (AUC) of spontaneous contractions were evaluated by 10 min intervals. Data were statistically analyzed by using the Wilcoxon Signed Ranks Test and Pearson?s Correlation Test.It was determined that all tested doses of ceftiofur reduced the frequency of contractions (P<0.05), did not affect the amplitude (P>0.05). After 500 µM and cumulative 1000 µM ceftiofur, the increase in the AUC found to be statistically insignificant (P>0.05). But after addition of cumulative 2000 µM ceftiofur the increase in the AUC found to be statistically significant (P<0.05).It was determined that application of 0.5 µM meloxicam to the isolated organ bath increased the frequency of contractions (P<0.05), cumulative 1.0 µM doses did not affect the frequency (P>0.05), cumulative 1.5 µM dose significantly reduced the frequency of contractions (P<0.05). Furthermore meloxicam significantly reduced the amplitude and AUC values of the contractions in a dose-dependent manner (P<0.05).In this in vitro study, it was found that all doses of ceftiofur reduced the frequency of contractions, did not affect the amplitude and increased AUC at high doses; low doses of meloxicam increased the frequency, did not affect at median doses, but reduced the frequency at high doses. All doses of meloxicam significantly reduced the amplitude and AUC. It was concluded that considering the effects of the agents observed in this study could be important during their clinical use at pregnancy and postpartum period.