Objective To observe the learning and memory abilities and the insulin-like growth factor-Ⅱ (IGF-Ⅱ) expressions in hippocampus of offspring rats after maternal rats exposed to stress before pregnancy, and to explore the mechanism of learning and memory abilities' alteration in offspring rats.
Methods A maternal rat model was established by using chronic mild stress stimulation protocol. Plasma cortisol levels of the maternal model rats were measured by radioimmuneassay. The abilities of learning and memory were determined using Morris water maze and Y maze, and the expressions of IGF-Ⅱ by real-time polymerase chain reaction.
Results Compared with the control maternal rats, the plasma cortisol levels of the maternal model rats were increased (P<0.05). Compared with the controls, the number of the model offspring rats and the days of maternal pregnancy in pregnant rats were less (P<0.05), but the male-to-female ratio was similar between the two groups (P> 0.05). The plasma cortisol levels of the model offspring rats were increased (P<0.05), while the learning and memory abilities (P<0.05) and the GF-Ⅱ mRNA expression levels (P<0.05) of the model offspring rats were decreased.
Conclusion The progestational maternal stress exposure may reduce the learning and memory abilities in the offspring rats, which may be associated with the decreased expression of IGF-Ⅱ and the increased plasma cortisol level.
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