Objective To investigate the effects of advanced maternal age (AMA) on synaptic pruning of the hippocampus of offspring rats. Methods Offspring of 3-month-old SD female rats and 3-month-old SD male rats were designated as the appropriate age group (Ctl group), while offspring of 12-month-old SD female rats and 3-month-old SD male rats were assigned to AMA group. Hippocampal tissues from both groups (n=3 per group at each time point) were subjected to Golgi staining on postnatal days (P) 7, 28, and 60. Dendritic complexity, spine density (DS), and morphology of immature brain neurons at different age stages were compared between the two groups. Results Compared with Ctl group, the dendritic length of AMA group on P7, P28, and P60 was significantly shortened, and the average number of intersections between dendrites and concentric circles on P28 and P60 was also significantly decreased (P<0.05). Compared with Ctl group, the dendritic spine density of AMA group was significantly decreased on P7, P28, and P60. Notably, the density of thin-shaped dendritic spines in AMA group was increased on P7, whereas the densities of stubby-shaped and mushroom-shaped dendritic spines were decreased (P<0.05). On P28 in AMA group, the densities of thin-shaped and mushroom-shaped dendritic spines were significantly increased compared with Ctl group, while the density of stubby-shaped dendritic spines was significantly decreased (P<0.05). The densities of stubby-shaped and mushroom-shaped dendritic spine were markedly lower in AMA group on P60 than those in Ctl group (P<0.05). Conclusions During postnatal brain development periods, there were abnormalities in synaptic pruning in the hippocampal region of the offspring of the AMA, which manifested as reduced dendritic complexity, decreased dendritic spine density, and disorganized dendritic spine morphology. It could be one of the key mechanisms underlying brain dysfunction in the offspring of AMA.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |