Hindawi Publishing Corporation Clinical and Developmental Immunology Volume 2013, Article ID 974205, 6 pages http://dx.doi.org/10.1155/2013/974205 Research Article Time-Dependent Effect of Oral Morphine Consumption on the Development of Cytotrophoblast and Syncytiotrophoblast Cells of the Placental Layers during the Three Different Periods of Pregnancy in Wistar Rats Leila Dehghani, 1 Hedayat Sahraei, 2 Rokhsareh Meamar, 3 and Masoomeh Kazemi 2 1 Department of Medical Sciences, Najafabad Branch, Islamic Azad University, Isfahan, Iran 2 Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran 1956837173, Iran 3 Isfahan Neurosciences Research Center, Isfahan University of Medical Science, Isfahan, Iran Correspondence should be addressed to Masoomeh Kazemi; mkazemih@yahoo.com Received 11 November 2012; Revised 15 January 2013; Accepted 16 January 2013 Academic Editor: K. Blaser Copyright © 2013 Leila Dehghani et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Previous studies have shown that morphine abuse during pregnancy cancause a delay in the development of the placenta and embryo and also bring about birth defects. Te present study investigates the efect of the duration of maternal morphine consumption during pregnancy, as well as the impacts of morphine abuse on the development of placental layers during the three diferent periods of pregnancy in Wistar rats. Materials and Methodology. Female Wistar rats have been used in the present study. Experimental groups received morphine (0.05 mg/mL of drinking water) afer one night of coupling with male rats for mating. On 9th, 10th, and 14th days of pregnancy, pregnant animals were killed, and placentas were removed and fxed. Te cells of the placentas layers were calculated by light microscope and MOTIC and SPSS sofware. Results. Te maternal surface thickness of the placenta was signifcantly increased, whereasthe fetal surface thickness of placenta was signifcantly decreased with morphine consumption with a time-dependent manner in experimental groups, compared to control groups. Moreover, the number of trophoblast cells increased in both maternal and fetal surfaces of placenta with respect to the duration of morphine consumption which was overt in the experimental groups compared to the control groups. Conclusion. In general, the time-dependent efects of oral morphine consumption can inhibit the development and natural functioning of cytotrophoblast and syncytiotrophoblast cells of the placental layers. 1. Introduction Opioid addiction is one of the major problems of the modern world. Te harmful consequences of drug abuse do not only afect the addicted person. As an instance, some preg- nant mothers abuse drugs and transmit the harmful efects of addiction to the future generations. Te present study examines the efect of the duration of morphine addiction on the severity of developmental delay in the placental cytotrophoblast cells. Since the placenta is the main source of material transfer between the mother and the fetus, it is thoroughly exposed to the risks of addiction. Te adverse efects of opioids in human subjects and in laboratory animals are well evident. Experiments have shown that opioid drugs harm the addicted mother and also cause abnormalities in the devel- opment of the placenta and embryo. For example, drug abuse by pregnant mothers leads to a delay in the placental development and causes fetal defects such as spina bifda [1, 2]. In addition, many symptoms have been reported in the newborns of opioid-addicted mothers. According to some research, these symptoms may be due to a delay in the diferentiation of the nervous system [2]. Also, since the placenta plays an essential role in fetal development, any kind