Research Paper Volume 11, Issue 17 pp 7257—7273

Figure 1. Genomic deletion of TLR2 accelerated cognitive impairments in mouse models of AD. Morris water maze tests (MWM) were performed on mice for seven consecutive days of place navigation processes, and a probe test was conducted on the 8^th day for mice aged 12 months. (A) Representative track plots of MWM for place navigation and probe tests. (B) The latency (time to find the hidden platform) increased in TLR2 knockout mice (&: TLR2KO vs. WT, p<0.05), AD mice (#: AD vs. WT, p<0.05), and AD-TLR2KO mice (+: AD-TLR2KO vs. WT, p<0.05). Moreover, the latency was prolonged in AD-TLR2KO mice compared with AD mice (*: AD-TLR2KO vs. AD, p<0.05). (C) Since mice have the habit of swimming along the pool, most of the mice searched the platform using an edge-type strategy on the first day of the test. As the tests progressed, WT mice converted to the tendency-type and straight-type searching strategies. However, compared with WT mice, AD mice exhibited a significantly higher ratio of the edge-type searching strategy (#: AD vs. WT, p<0.05). In addition, the ratio of the edge-type strategy in TLR2KO mice was significantly higher than that in WT mice (&: TLR2KO vs. WT, p<0.05). Importantly, the ratio of the edge-type strategy increased in AD-TLR2KO mice compared with AD mice (*: AD-TLR2KO vs. AD, p<0.05). (D and E) In the probe test, the frequencies of crossing the platform area in AD, AD-TLR2KO, and TLR2KO mice were significantly lower than those in WT mice (p<0.05, D). The time spent in the target quadrant among AD, AD-TLR2KO, and TLR2KO mice was significantly less than that among WT mice (p<0.05, E). However, there was no difference in the frequencies of crossing the platform area or in the time spent in the target quadrant between AD and AD-TLR2KO mice (Note: &: TLR2KO vs. WT, p<0.05; #: AD vs. WT, p<0.05; +: AD-TLR2KO vs. WT, p<0.05; *: AD-TLR2KO vs. AD, p<0.05. n=11~15/group).