Figure 1.
The experimental timeline of this study.
Body weight (BW) and blood glucose (BG) were measured on days 1, 10, 32, and 39. ELISA, western blot, and immunohistochemistry (IHC) were performed for protein analysis. Spatial learning and memory was evaluated by the Morris water maze (MWM).
Figure 2.
The body weight, blood glucose, and insulin level of the mice.
Gain in body weight was not affected by LPS or EX-4 treatment in the normoglycemic (A) and hyperglycemic (B) mice. EX-4 treatment continuously decreased blood glucose (C) and increased insulin (D) in the hyperglycemic mice. Data are expressed as means ± S.E.M. (n = 15–20 per group for body weight and blood glucose, n = 6 per group for insulin). * p<0.05; ** p<0.01; *** p<0.001.
Figure 3.
Effects of hyperglycemia, LPS and EX-4 on spatial reference learning and memory.
The mouse learning curve is shown in (A). Intrahippocampal LPS injection exacerbated the impairment of spatial learning acquisition (B) and spatial memory retrieval (C) in the hyperglycemic mice. In addition, EX-4 treatment protected against the impairment of spatial learning acquisition (D & E) and spatial memory retrieval (F) following intrahippocampal LPS injection in the normoglycemic or hyperglycemic mice. These results were independent of the swimming velocity (G). Data are expressed as means ± S.E.M. (n = 15–20 per group). * p<0.05; ** p<0.01; *** p<0.001.
Table 1.
The levels of IL-1β in the plasma and hippocampus of each group at different time points.
Figure 4.
The levels of inflammation and oxidative stress in the mouse hippocampus on day 12.
The expression levels of TLR4 (A), COX1 (B), COX2 (C), NF-κB (D), CD45 (E), iNOS (F), and MnSOD (G) in the mouse hippocampus were measured by western blot analyses. Data are normalized to β-actin and expressed as the mean ± S.E.M. (n = 3–5 per group). * p<0.05; ** p<0.01; *** p<0.001.
Figure 5.
The levels of inflammation and oxidative stress in the mouse hippocampus on day 39.
The expression levels of TLR4 (A), COX1 (B), COX2 (C), NF-κB (D), CD45 (E), iNOS (F), and MnSOD (G) in the mouse hippocampus were measured by western blot analyses. Data are normalized to β-actin and expressed as the mean ± S.E.M. (n = 3–5 per group). * p<0.05; ** p<0.01; *** p<0.001.
Table 2.
The responses of inflammatory-related proteins in the hippocampus of mice receiving different treatments at different time points.
Figure 6.
Immunohistochemical analysis of microglia and astrocytes in the mouse hippocampus.
(A–H) Representative immunostainings of microglia by Iba1 antibody in the mouse hippocampus. (I–P) Representative immunostainings of astrocytes by GFAP antibody in the mouse hippocampus. Scale bar = 50 µm. Arrowheads indicated positive staining for activated microglia and astrocytes, which are magnified in the insets of each figure (n = 3–5 per group).
Table 3.
The immunohistochemistry results in mice receiving different treatments.
Figure 7.
Immunohistochemical analysis of noradrenergic and serotonergic neurons.
(A–H) Representative immunostainings of noradrenergic neurons in the locus coeruleus (LC) region. (I–P) Representative immunostainings of serotonergic neurons in the Raphe nucleus. Scale bar = 100 µm. Arrowheads indicate positive staining signals (n = 3–5 per group).
Figure 8.
Immunohistochemical analysis of apoptosis in the mouse hippocampus.
(A–H) Representative immunostainings of caspase 3 are shown in the CA1 subregion of the hippocampus. Scale bar = 50 µm. Arrowheads indicate positive staining signals (n = 3–5 per group).