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[Effects of paraquat on the learning and memory ability in developing mice]
Yong-Hong Sun1, Yao Li, Yu-Jie Niu
1Department of Toxicology, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China.
Objective:
To explore the damages of paraquat to the learning and memory ability of developing mice and explore the possible mechanism involving oxidative stress.
Methods:
Eighty healthy Kunming mice in aged 21 days were divided into 4 groups randomly: a control group (distilled water) and three paraquat treatment groups. The doses of paraquat were 0.89, 2.67 and 8mg/kg body weight, respectively. Paraquat was administered orally in doses of 0.1 ml/10 g body weight, respectively, once a day and for 28 consecutive days. The Morris water maze test and the shuttling and avoid dark box test were used to detect the learning and memory abilities of mice. The levels of MDA and the activities of SOD and GSH-PX were detected according to the commercial kits manual using a microplate reader.
Results:
Morris water maze test showed that the escape latency of mice after paraquat treatment (57.98 +/- 2.78, 62.35 +/- 3.18, 85.57 +/- 5.10) were significantly increase compared with the control (21.74 +/- 1.36), respectively (P < 0.05). There were good dose-response relationship (R = 0.8629, P < 0.05). The shuttling and avoid dark box test showed that initiative avoidance latency of mice after paraquat treatment (5.56 +/- 0.29, 6.08 +/- 0.22, 8.32 +/- 0.38) were significantly increase compared with the control (3.50 +/- 0.13), respectively (P < 0.05). There were good dose-response relationship (R = 0.9579, P < 0.05). The levels of MDA in serum of mice in paraquat treatment groups (2.67 and 8 mg/kg) (24.76 +/- 1.76, 31.10 +/- 4.57) and in hippocampus of mice in each paraquat treatment groups were significantly increase compared with the control (serum: 16.38 +/- 6.26, hippocampus: 1.93 +/- 0.39) (P < 0.05, respectively). The activities of SOD in serum and hippocampus of mice in each paraquat treatment groups were significantly decrease compared with the control (serum: 213.25 +/- 6.78, hippocampus: 197.36 +/- 6.37) (P < 0.05, respectively). The activities of GSH-PX in serum and hippocampus of mice in each paraquat treatment groups were significantly decrease compared with the control (serum: 583.47 +/- 11.23, hippocampus: 412.38 +/- 13.16) (P < 0.05, respectively).
Conclusion:
Paraquat can induce the oxidative damage in hippocampus, and then influence the learning and memory abilities of developing mice.
Insights
Paraquat exposure impairs learning and memory in developing mice by inducing oxidative stress in the hippocampus. This study highlights the neurotoxic effects of paraquat on cognitive functions in young animals.
Area of Science:
- Neuroscience
- Toxicology
- Developmental Biology
Context:
- Paraquat is a widely used herbicide with known toxicity.
- Developing brains are particularly vulnerable to environmental insults.
- Understanding the neurotoxic mechanisms of paraquat is crucial for public health.
Purpose:
- To investigate the impact of paraquat on learning and memory in developing mice.
- To elucidate the role of oxidative stress in paraquat-induced neurotoxicity.
Summary:
- Developing mice were exposed to paraquat orally for 28 days.
- Learning and memory were assessed using the Morris water maze and shuttle box tests.
- Oxidative stress markers (MDA, SOD, GSH-PX) in serum and hippocampus were measured.
Impact:
- Paraquat significantly impaired learning and memory in a dose-dependent manner.
- Paraquat exposure led to increased oxidative stress in the hippocampus.
- Findings suggest paraquat-induced hippocampal oxidative damage contributes to cognitive deficits in developing mice.
