Effects of stress-induced depression and antidepressant drugs on CA3 region of hippocampus in adult albino rats

Introduction: Hippocampus is the most extensively studied part of the brain in recent years. The connections of the hippocampus are extensive and very complicated, covering lots of functions in the body. The aim of the study is to find out the effect of stress-induced depression in the CA3 region of the hippocampus and also to see the effect of antidepressants for the reversal of changes in the similar area. Material and Methods: The study conducted on adult albino rats weighing 200-250 g. The study involved 50 albino rats and divided into five groups. The first group was control of ten rats and received water and food ad libitum, and the second group was experimental having two subtypes E1 and E2 receiving 4 weeks and 7 weeks immobilization with ten rats each, respectively. The third is treatment group which has two subtypes T1 and T2 for 4- and 7-week treatment by fluoxetine drug (1 mg/kg body weight orally) with ten rats each, respectively. The animals sacrificed after the experiment, perfused with 10% formaldehyde, brains dissected, and tissue blocks processed for paraffin embedding. Observations were made on 5-mu thick H and E-stained sections. Estimation of neuronal density of CA3 regions performed using Motic Images Plus 2.0 software (Hong Kong China). Results: Neuronal density was markedly reduced (98.7 +/- 6.1 cells/cubic mm) in acute depression and 66.3 +/- 4.8 cells/cubic mm in chronic depression group, respectively, as compared to control (124.5 +/- 7.2 cells/cubic mm). The density improved after giving drug treatment. Neuronal density was 111.2 +/- 9.6 cells/cubic mm and 92.3 +/- 5.5 cells/cubic mm in 4- and 7-weeks treatment, respectively. Discussion and Conclusion: These results suggested that neurodegenerative effects of depression on the hippocampus, which is reversed by giving antidepressant drug.