EFFECT OF CHRONIC ADMINISTRATION OF OPIOIDS (MORPHINE) ON GROWTH AND INTESTINAL MUCOSA IN MOUSE STRAIN BALB/C

Apart from the nervous system, the digestive system has the maximum opioids receptors which it indicates importance of the opioids in this system. It seems that morphine and other opiods compound have major harmful effects on intestinal tissue. Purpose of this study is to examine of the long-termed use of the morphine on growth and histomorphological structure of digestive system in mice strain Balb/c. Some mice were selected from three age groups (premature, mature and from premature to full mature). One hundred fifty mice (at the age of 21 days) were divided to 12 groups randomly. Groups consisted of six test groups (20 mice in each group), three control groups (5 mice in each group) and three sham groups (5 mice in each group). Control groups were maintained on stock dieted of tap water while sham groups dieted with tap water and sugar (5mg/ml). Test groups also used tap water, sugar and two different dosages of morphine (0.01mg/ml or 0.1mg/ml). Our study showed that in all tests groups, the chronic administration of escalating doses of the morphine caused decrease of the weight of mice. In addition, the long -termed use of morphine caused histological changes in small intestine and colon in all the groups of age. Invasion of mononuclear cell (especially lymphocyte) to mucosa was the most important histological change. In addition, villous height and intensity also decreased. This study suggested that the chronic consumption of opioids causes pathological change in gasterointestinal system. Vet. Res. Bull. 6,2:176-181, 2011.