3.6 Synaptic plasticity was impaired in both PrL and IL in
ICV-STZ rats and reversed by 1-MT.
It has been acknowledged that neuroinflammation can influence both
neurogenesis and neuroplasticity. Golgi staining can visually observe
the dendritic spines, thereby reflecting changes in synaptic plasticity
and function (Figure 9A). Additionally, BDNF is a dimeric protein used
to delineate neuroplasticity. In the PrL, the main effects of ICV-STZ
were observed in the total spine density
(F(1,20)=55.46), mushroom type
(F(1,20)=37.50) and levels of BDNF
(F(1,20)=11.73); the main effects of 1-MT treatment were
observed in the total spine density (F(1,20)=39.21),
mushroom type (F(1,20)=10.36) and levels of BDNF
(F(1,20)=19.42). A significant interaction between
ICV-STZ and 1-MT treatment was observed in the total spine density
(F(1,20)=26.53), thin type
(F(1,20)=4.376), filopodia type
(F(1,20)=4.543), mushroom type
(F(1,20)=11.06) and levels of BDNF
(F(1,20)=23.22). For IL, the main effects of ICV-STZ
were observed in the total spine density
(F(1,20)=16.10), mushroom type
(F(1,20)=5.068) and levels of BDNF
(F(1,20)=9.407); the main effects of 1-MT treatment were
observed in the total spine density (F(1,20)=27.29),
mushroom type (F(1,20)=21.27), stubby type
(F(1,20)=10.09) and levels of BDNF
(F(1,20)=7.88). A significant interaction between the
ICV-STZ and 1-MT treatment was observed in the total spine density
(F(1,20)=32.82), mushroom type
(F(1,20)=21.57), stubby type
(F(1,20)=18.78) and levels of BDNF
(F(1,20)=5.012). The post hoc test showed that ICV-STZ
rats displayed a drastic decrease in dendritic spine density and the
proportion of mushroom in both PrL and IL, and these abnormalities were
reversed by intra-PrL or IL injection of 1-MT (Figure 9B-G). In another
aspect, the proportion of thin and filopodia was increased significantly
in the PrL by ICV-STZ, intra-PrL injection of 1-MT reversed the increase
of thin, but the increase of filopodia was slightly and not
significantly blocked by 1-MT (Figure 9D). In contrast, the proportion
of stubby was increased significantly in the IL by ICV-STZ, which was
reversed by intra-IL injection of 1-MT (Figure 9G). The expression of
BDNF in the PrL and IL were both remarkably decreased in ICV-STZ rats,
and intra-PrL and IL administration of 1-MT can reverse the decreased
BDNF levels induced by ICV-STZ (Figure 9H-K).