Abstract

Background: We have previously reported that maternal administration of Boswellia serrata gum resin (Frankincense) during lactation increased learning and memory performance in young rat offsprings. This study aimed to determine the likely structural alterations of hippocampus, as a vital centre involved in learning and memory, following administration of Frankincense during lactation Methods: In this experimental study, 2 month-old male Wistar rats whose mothers were given oral aqueous extract of the Boswellia serrata (100 mg/kg/day) during lactation (3 weeks), and their controls whose mothers received saline (n = 6) were anesthetized and transcardially perfused. All brains were removed and divided into two hemispheres. One hemisphere was selected for estimating the volumes of cellular layers of hippocampus and the total number of neurons, and the other for estimating the individual somal volume. The Cavalieri's principle and an optical fractionator and a rotator were employed to estimate the volumes of layers, total number of neurons and individual neuronal volume, respectively. Findings: Our results showed that no significant difference in the total number of neurons in hippocam-pal subregions of the experimental group compared to the controls. However, the volume of cellular layer of dentate gyrus and cornu ammon 3(CA3) and individual volume of their neurons increased following maternal administration of Frankincense during lactation. Conclusion: The increased perikaryal volume in the hippocampal neurons of offsprings following maternal administration of Frankincense during lactation might be considered as an indicator of improved function of hippocampus, i.e. memory. It might be due to the increases in contents of neurons such as neurotransmitters, intracellular organelles or the number of synaptic contacts.