Evaluating the Protective Effects of Melissa Officinalis on Learning Deficits of Rat's Offspring Exposed to Lead Acetate During Pre- and Postnatal Periods

Introduction &

Lead contamination dramatically influences different body systems especially the central nervous system. Lead absorption during gestational period has deleterious effects on fetal differentiation and development and it may possibly result in learning deficits in adulthood. Recent studies have demonstrated positive effects of Melissa officinalis on memory improvement in some neural disorders. The aim of the present study is to investigate the protective effects of Melissa on learning deficits in lead acetate exposed rats.

In this experimental study in department of Biology, Faculty of Sciences, Ferdowsi University of Mashhad (2008-2009), 40 mated Wistar rats were divided into 8 groups as follows: control, negative control (Pb), Melissa (M) and Pb+M, and each in 3 different subgroups. The treatment started from the 7th day of gestation and continued during pregnancy and lactation. The learning ability and memory retention of four months old offspring were tested by complex T-maze. The collected data was analyzed by the SPSS software using one-way ANOVA and Toki test.

A significant difference was found between lead exposed group and other groups regarding the time to reach the goal and the number of errors; while there was no meaningful difference between the control and other experimental groups.

In lead exposed rats, learning deficits were obviously noticed. Since there was meaningful difference between control and Pb+M subgroups, Melissa can possibly improve learning deficits in lead acetate exposed rats.