Fig. 4

Mild ER stress inhibited LPS-induced apoptosis in the hippocampus and ameliorated the cognitive decline. a Contextual fear response, as measured by freezing time, was determined in the rats (n = 12). b The number of learning trials was recorded to analyze the Y-maze test (n = 12). Each value was expressed relative to that of the naïve group, which was set to 100 (n = 6). c The TUNEL assay was performed to determine the extent of apoptosis in the CA1 area of the hippocampus. The arrows indicate cells showing an overlay of TUNEL and DAPI signals. Scale bar, 100 μm. d Quantitative analysis of TUNEL-positive cell content in different groups. The data are representative of three independent experiments. *P < 0.05, **P < 0.01 vs. naïve group. #P < 0.05, ##P < 0.01 vs. LPS treatment group. ^P < 0.05, ^^P < 0.01 vs. TM treatment group. The data are presented as the mean ± SEM