Evaluation of some oxidative stress markers due to morphine abuse in horses

In recent years, popularity of horse-riding has increased which has caused many consequences and problems. One of the important issues raised in equestrian sports is the abuse of different drugs for doping. It has been reported that flunixin meglumine has been mainly used for doing of horses in recent years in Iran and also most of doping cases are of morphine type. In this study, urinary morphine detection kit, with the ability to detect at least 300 mg/ml morphine in urine, manufactured by a France company named ABON® was used for detection of morphine. The oxidative effects of morphine in horses was also investigated. For this purpose, 36 horses of both sexes (26 horses in the experimental group and 10 horses as the control) were obtained. Horses in the experimental group were intramuscularly treated with 0.4 mg/kg morphine sulfate produced by Daroo Pakhsh Company. In addition, 10 control horses received distilled water by the same amount. Then, urine samples were collected 3, 24, and 48 hours after administration and tested using a detection kit. The results showed that morphine test in 100%of horses treated with morphine sulfate was positive in urine samples collected 3 and 24 hours after the administration, while the test results was negative in all horses that received distilled water. The mean levels of serum malondialdehyde (MDA) in the control group 892/0 ± 544/3 nmol / ml and in the test group 87/0 ± 185/3 nmol / ml that the mean difference between groups was not significant. The mean serum total antioxidant status (TAS) was 329/0 ± 78/0 mmol / Lin the control group and 40/0 ± 362/1 mmol / L in the experiment group that was significantly higher in the experimental group ( p=0.001).In this study it was found that the use of morphine in horses can cause oxidative effects.