Neonatal Long-Evans rat pups were given the standard dose, 600 mg of lead acetate per kg of body weight every 24 hours beginning one day after birth until a cumulative dose of 2400 mg/kg (4 doses) had been administered via stomach intubation. Blood lead levels in lead treated rats averaged 526.35 micrograms/dl at 10 days of age. Blood lead values in age-matched controls averaged 0.079 microgram/dl. The body weights of the lead treated rats were not significantly different than control rats at 30 days of age. The brain weights were significantly greater than those of control rats at 30 days. Camera lucida drawings of pyramidal cells from motor cortex of control rats contained significantly (54%) more secondary and tertiary branches extending laterally from the primary apical dendrite than pyramidal cells of lead treated rats. The dendritic branches were numbered according to their branching point away from the soma. There was a significant reduction in the number of 4, 5, 6, and 7th order branches extending from the apical dendrite and 3 and 4th order branches extending from the basal dendrites in the leaded-rats. The mean dendritic length was reduced by 19% in basal dendrites and by 28% in apical dendrites. Measurements of dendritic material by the Scholl method revealed 17% reduction in the basal dendrites and a 36% reduction in the apical dendritic material in treated rats. These results suggest that neonatal lead exposure alters the dendritic development of pyramidal cells of rat motor cortex.

Animals↗

PubMedDate not supplied

The effects of postnatal lead toxicity on the development of cerebellum in rats.

Long-Evans hooded rat pups were given 600 mg/kg body weight lead acetate every 24 hours via stomach intubation beginning one day after birth until an accumulative dose of 2400 mg/kg was administered. The body weights of the lead treated rat pups at 10 and 30 days of age were not significantly decreased when compared to controls. The brain weights at 10 and 30 days of age in the lead exposed rats was significantly greater than those of the control rats. Blood lead levels averaged 526.35 micrograms/dl at 10 days of age in lead treated rats and 0.079 microgram/dl in controls. Quantitative histological examination and Golgi analysis of the cerebellum revealed a number of alterations in the lead treated rats. Lead exposure resulted in a significant decrease in the molecular layer width (72%). The granule cell density was depressed in the lead exposed rats, despite the observation that the granule cell layer width did not differ significantly in the two groups. This suggests that the granule cell packing in this layer was decreased. The Golgi study revealed a reduction in the dendritic arborization of these cells in the treated rats at 30 days of age. There was a 20% reduction in height and a 14% reduction in width in the Purkinje cells dendrites of the lead exposed rats when compared to Purkinje cells of age matched controls. Estimation of the amount of dendritic material by the Scholl method revealed a 40% decrease in the dendritic arborization of Purkinje cells following lead exposure.

Animals↗

PubMedDate not supplied

Input: proposed denturist bills.

Explore the source record for details and available documents.

Dental Technicians↗