Maternal exposure to atrazine induces the hippocampal cell apoptosis in mice offspring and impairs their learning and spatial memory

Abstract

Background: The atrazine is widely used in the world as herbicide. It has been shown that atrazine can transmit from mother to their offspring via the placenta and the breast milk. Recent studies also confirmed that atrazine has ability to damage to the central nervous system. Since hippocampus is an important part of the brain that plays a key role in memory and learning, we evaluated the effects of atrazine exposure during pregnancy and lactation on the hippocampal cells and spatial memory in the male offspring of mice.

Materials and methods: Twenty four pregnant Balb/C mice were divided into three groups of atrazine 10 mg/kg, atrazine 50 mg/kg and normal saline (n = 8). Atrazine and normal saline were given by gavage to the animals. Daily treatment with atrazine or normal saline began from gestational day (GD) 6 and continued until postnatal day (PD) 23. At the end of the treatments, brains of the male offspring were collected and histological studies were performed to detect apoptotic cells and dark neurons (DNs) in their hippocampus. Moreover, eight male offspring from each group were weaned and housed until adulthood (PD75). Then, learning and spatial memory were examined using Morris water maze (MWM) and passive avoidance (PA) tests.

Results: The histological results of this study showed that apoptotic cells and DNs were significantly high in the offspring hippocampus in atrazine-exposed groups. Furthermore, the results of the behavioral tests indicated that learning and memory of offspring in the atrazine groups were significantly lower than in the normal saline group.

Conclusions: Maternal exposure to atrazine during pregnancy and lactation periods increases the apoptotic cells and DNs in the hippocampus of the mice offspring and impairs their learning and spatial memory.

Keywords:

• Atrazine
• hippocampus
• apoptosis
• spatial memory
• Morris water maze

Acknowledgments

The results described in this paper were from an MSc student thesis. The authors would like to express their sincere thanks to vice chancellor for research, Mashhad University of Medical Sciences for the financial support [No. 940025].

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to express their sincere thanks to vice chancellor for research, Mashhad University of Medical Sciences for the financial support [No. 940025].