Effect of long-term treatment of morphine on enzymes, oxidative stress indices and antioxidant status in male rat liver.

In this study, biochemical changes due to long term usage of morphine in rat's liver were assessed. Twenty male Wistar rats (180-220 g) were included and divided into two groups. Normal saline was given intraperitoneally in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4, 8, and 10 mg/kg/day in the first, second and the third ten days of the study, respectively. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and liver malondialdehyde (MDA) level as well as activities of superoxide dismutase (SOD), glutathione-s-transfrase (GST) and catalase (CAT) were measured. Serum levels of AST, ALT and LDH were significantly higher in the morphine group compared with the control group. The mean MDA level of liver was significantly higher in the morphine group compared with the control group (P < 0.05). The activities of SOD, GST and CAT were significantly lower in the morphine group compared with the control group (P < 0.01). Our findings pointed out the risk of hepatic damage due to long term usage of morphine via disturbance oxidant-antioxidant balance. Although morphine is showed to be effective in pain treatment, their toxic effects should be kept in mind during the chronic usage.