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Depression is a dilapidating disorder, which may occur during pregnancy. Citalopram is an antidepressant drug often prescribed to pregnant women. The purpose of the present study is to determine whether maternal administration of citalopram affects fetal liver histology.
Pregnant Wistar albino rats were treated with citalopram (10 or 20 mg/kg/day). A control group received no treatment. Rat fetal liver samples were obtained on day 18 of gestation and evaluated morphologically and histologically.
Statistical evaluation of data showed that there were no differences in liver weight and relative liver weight between control and citalopram treatment groups. Liver histology changes (such as increases in the number of Kupffer cells and lymphocytes) were seen in the fetuses of the group receiving a high dose of citalopram during gestation. Degeneration of hepatocytes was not seen and the megakaryocyte number did not change significantly in the citalopram treated groups.
This study showed that citalopram administration during gestation may have some adverse effects on the phagocytic cell population in the fetal liver of rats.
The prevalence of depression in pregnancy is approximately 10% and up to 20% of women experience depressive symptoms during pregnancy. Selective serotonin reuptake inhibitors (SSRIs) are the pharmacological treatment of choice for depression, anxiety and obsessive-compulsive disorder. Moreover, these drugs are specifically recommended for the treatment of these disorders during pregnancy and lactation.[2,3] Citalopram is one of the frequently used antidepressant drugs of the SSRI class. This drug is metabolized extensively by the liver. In experimental animals, the drug was found to induce a fatty liver. A metabolite generated through its first-pass metabolism has been suggested to be responsible for the liver toxicity. In addition, there was one case report in 2004 describing damage caused by citalopram to human liver. Significant citalopram and its metabolite concentrations have been detected in both umbilical cord blood and amniotic fluid in women taking this medication during pregnancy. Health of the fetal liver is very important since it is a principal hematopoietic organ. At birth, it undergoes dramatic morphological and functional changes as the number and volume of hepatocytes increase, whereas hematopoietic cells diminish in number. Extracellular matrix (ECM) components also serve many functions including the provision of structural support and attachment sites for cell surface receptors, plus roles in cell migration, cell proliferation, orientation, immune responsiveness and tissue and organ morphogenesis. The cellular sources of individual ECM proteins in the liver have been reported to be derived from hepatocytes, lipocytes and sinusoidal cells.
Considering the importance of fetal liver and transplacental passage of citalopram a study on the effect of citalopram on fetal liver was envisaged.
The aim of this study is to evaluate the histological changes of fetal liver due to citalopram administration in pregnant rats.
Citalopram was provided by Ramopharmin Pharmaceutical Company (Tehran, Iran), Hematoxylin and Eosin (H and E) were purchased from Fisher Healthcare (USA), ethanol, chloroform, acetic acid, paraffin, xylol and other chemicals were obtained from Merck (Germany).
Wistar albino virgin female rats aged 12 weeks used in this study were raised in the laboratory of Tarbiat Moallem University, Faculty of Science and Department of Biology. The animals were maintained in a controlled environment under standard conditions of temperature and humidity with an alternating 12:12 h light/dark cycle and were fed with standard pellet chow ad libitum throughout the experiment. Animals were mated at night and examined for a vaginal plug. The presence of a plug indicated conception and that day was considered as gestation day 1 (GD 1). The policy of Experimental Animals Production Center, Kharazmi University, Tehran, Iran, established for the care and use of laboratory animals, was followed in all experiments. Moreover, the approval for this research was obtained from the ethics committee of Kharazmi University, Tehran, Iran.
The rats were divided into three different groups, each containing at least six pregnant rats, which received the following treatments: Test Group A: Rats received the 10 mg/kg/day citalopram, Group B: Rats received the 20 mg/kg/day citalopram and control group: Without any treatment. Dose selection in this study was performed based on previous findings, which demonstrated that the serum and brain concentration of citalopram were within the therapeutic range after administration of 10-20 mg/kg/day in adult rats. Citalopram was dissolved in sterile water for injection and treatments were administered subcutaneously during the pregnancy (GD 1 to GD 18). The body weight of pregnant rats in all experiment groups were measured daily. The body and the liver weights of fetuses were determined at the end of the experiment. The pregnant rats in each experimental group were sacrificed by cervical dislocation on GD 18. All animals were sacrificed at the same time of day. The uterus was opened and the fetuses were removed. Fetus and liver were weighed and then liver samples were immediately fixed. The histology slides were prepared according to a standard procedure. Briefly, tissue specimens were fixed using 10% neutral buffered formalin. Then, they were transferred to cassettes. After that, dehydration, clearing and embedding were performed using ethanol, xylene and paraffin wax respectively. Finally, 5 μm tissue sections were cut using microtome. Sections were stained with H and E and then examined under light microscopy. The number of megakaryocytes, kupffer cells and lymphocytes were counted over the entire slide. Since the number of fetuses was different in each pregnant rat, the group sizes were not the same (Group A: n = 56, Group B: n = 50, control group: n = 52). A total of 1500 sections were evaluated (500 sections per group).
Data were expressed as mean ± standard error. Statistical analysis was performed using analysis of variance and the significance level was defined as P < 0.05. Data were analyzed by GraphPad Prism statistical software (version 5.04 for Windows, GraphPad Software, San Diego California USA, www.graphpad.com).
Mortality was not observed in any of the study groups. The weight of the mothers was 275 ± 25 g. Statistical evaluation did not show significant differences in fetal body weight, liver weight or relative liver weight between control and citalopram treatment groups [Table 1].
Fetal liver sections were stained with H and E for histological investigation. No degeneration of hepatocytes in the citalopram treatment groups was observed [Figures [Figures11--3].3]. Moreover, the number of megakaryocytes in the groups receiving citalopram during pregnancy was not different from the control group [Figure 4].
Whilst there were no significant differences between the control and test groups in terms of the number of megakaryocytes, considerable differences were observed in the number of kupffer cells and lymphocytes in the liver of fetuses of the test Group B in comparison with the control group [Figures [Figures55 and and66].
Citalopram is a SSRI approved for the treatment of major depressive disorders. Because approximately 50% of all pregnancies are unplanned and depression is a severe situation diagnosed during pregnancy, there is a great attention in ensuring the fetal safety of SSRIs especially citalopram. The results of our study showed no significant differences in fetus liver weight between the control rats and treatment groups [Table 1]. The finding is in agreement with the results of preclinical animal teratology studies which showed, citalopram exposure in pregnant rats did not generate dramatic morphological toxicity in the fetuses. In addition, degeneration of hepatocytes was not seen in the fetuses of the rats in the treatment groups [Figures [Figures11--3].3]. Since the degeneration in hepatocytes may be seen prior to the development of necrosis or in non-necrotic cells surrounding zones of necrosis, the lack of any cytoplasm degeneration reveals that there was no necrosis in the liver tissue of test groups.
Further histological studies showed that citalopram administration by pregnant rats did not influence the number of megakaryocytes [Figure 4] whereas, Kupffer cells and lymphocytes in the fetuses of the group who received citalopram at a dose of 20 mg/kg/day during gestation increased significantly [Figures [Figures55 and and6].6]. Statistical analysis demonstrated that the increase in number of the Kupffer cells and lymphocytes was dose dependent. Thus, at a dose of 20 mg/kg/day the cell number increase was significant, whilst at a dose of 10 mg/kg/day it was not.
Kupffer cells [Figure 7] constitute a major non-parenchymal cell population of the liver. A key function of hepatic Kupffer cell is the removal of a wide range of foreign and potentially harmful substances from the portal and systemic circulation. Equally important is the cells ability to subsequently degrade these materials. The large lysosomal component (13.5% of the cell volume) of the Kupffer cell, together with its high specific activity of lysosomal enzymes, suggests a considerable capacity to degrade ingested substances. The liver also contains a large resident and migratory population of lymphocytes [Figure 8] that provide immune surveillance against foreign antigens. This population can be rapidly increased in response to infection or injury by hiring leucocytes from the circulation. Therefore, knowing the phagocytic role of Kupffer cells and lymphocytes, it can be concluded that increasing the number of these cells can be due to liver encountering with the detrimental substances. It means that citalopram or its metabolites are assumed as harmful substances by the rat fetus liver. Compared with the Kupffer cells and lymphocytes, the number of megakaryocytes in the fetuses of groups receiving citalopram at a dose of 10 or 20 mg/kg/day during the pregnancy did not change significantly. In view of the fact that megakaryocytes are responsible for the production of blood thrombocytes (platelets), their unchanged number indicates that the hematopoietic role of the liver is not influenced by citalopram or its metabolites.
The results obtained from this study show that the number of Kupffer cells and lymphocytes of fetal liver was affected significantly by maternal citalopram treatment. However, additional studies will be necessary for accurate evaluation of the effects of citalopram on the fetal liver.
This work would not have been possible without the invaluable excellent technical assistant of following colleagues: Miss Hemmati and Miss Beyrami.
Source of Support: Nil
Conflict of Interest: No