Stereological Study of Oocyte Volume and Ovarian Follicles of Adult Rats During Prenatal and Lactation Periods under Conditions of Lead Poisoning

BACKGROUND: The pollution of environment with heavy metals following the increase in the industrial production has created problems in the lives of living organisms. Lead can penetrate the soft organs of body, and by depositing in them can cause disorders their function. Lead can cross the blood-placental barrier and transfer to the fetus. It is also possible to pass lead through milk to the newborn.OBJECTIVES: The stereology approach was used in rats as animal models to examine the impact of low dosage lead contamination in the mother on the average volume of follicular oocytes and the average volume of mature follicles.METHODS: Wistar rats were randomly divided into five groups, which included a control group and four experimental groups of pre-pregnancy, pregnancy, lactation and pre-pregnancy-pregnancy-lactation. The control group had access to drinking water with 0.5 ml of glacial acetic acid. Experimental groups administered lead acetate at a rate of 0.2 percentage + 0.5 ml of glacial acetic acid through drinking water in different periods (pre-pregnancy group 30 days before mating, pregnancy group 21 days of pregnancy, lactation group. They received 21 days of lactation and the pre-pregnancy-pregnancy-lactation group 30 days before mating until the end of lactation). On the 65th day after birth, all infants were killed in the laboratory and left ovary specimens were collected for stereological studies.RESULTS: The results showed that the average volume of oocytes in the primordial, monolayer primary, multilayer primary, and antral follicles increased in the lactation group compared to the control group and other experimental groups (P<0.05). Furthermore, the mean volume of primordial and monolayer primary follicles in lactation group increased compared to the control and experimental groups (P<0.05).CONCLUSIONS: This study's results showed that maternal exposure to low doses of lead during lactation increases the average volume of oocytes and increases the average volume of growing follicles.