Prenatal and early postnatal are the most sensitive and high-risk periods to expose to electromagnetic fields (EMFs). This study aimed to investigate the effect of prenatal and early postnatal exposure to 900 MHz radiofrequency waves (RFWs) emitted from a base transceiver station antenna on passive avoidance learning and memory (PALM) and hippocampus histomorphology. Female Sprague Dawley rats (190–230 g) were paired with males. The mated rats, confirmed by observing a vaginal plug, were divided into two groups; control and exposed. The control group ( n = 7) was not exposed to RFW. The exposed group was divided into three subgroups ( n = 8); exposed Ⅰ, exposed during the gestational period (fetal life), and exposed Ⅱ and Ⅲ (postnatal exposure), exposed to RFW during the first 21 days of life, for 2 h/d and 4 h/d, respectively. PALM was evaluated by a shuttle box in 45-day-old pups. Learning and memory of animals were demonstrated as the duration of remaining within the light area, which is called the lighting time. Histological sections were prepared from brain tissues and stained with hematoxylin and eosin. An impairment in the PALM performance was noticed in all exposed subgroups (Ⅰ, Ⅱ, and Ⅲ) ( p < 0.05). Learning (short-term memory) and retention (long-term memory) behaviors were more affected in exposed subgroup Ⅰ (prenatal exposed) compared to other postnatal exposed subgroups (Ⅱ and Ⅲ). Also, a mild decrease in the density of pyramidal cells was observed in the hippocampus of exposed subgroups (Ⅰ and Ⅲ). Prenatal and early postnatal exposure to 900 MHz RFW adversely affected PALM performance and hippocampus tissue in rat pups with more impact for prenatal period exposure.
Effect of a hydro-alcoholic extract of Melissa officinalis on passive avoidance learning and memory
