Bone marrow transfer from AD mice causes cognitive deficits in APP KO recipient mice
APP KO recipient mice with a successful reconstitution of donor BMCs were assessed for their cognitive status, using tests designed for the analysis of different aspects of memory. The data were pooled from two different trials unless stated otherwise and are represented as the mean ± standard deviation.
(A–D) Open-field test (OFT). (A) APP KO mice that received BMCs from WT mice (WT→APP KO) spent significantly less time in the center of the field compared to APP KO mice that received BMCs from AD mice (AD→APP KO). (B) There was no significant difference in the distance traveled in the open field between WT→APP KO mice and AD→APP KO mice. (C) AD→APP KO mice have a significantly higher number of entries in the central squares of the field than WT→APP KO mice. (D) Representative track plots from the OFT. WT→APP KO mice spend less time exploring the open center of the test arena while AD→APP KO mice explore the entire field indiscriminately. Each plot in the figure represents the track from a different mouse. (A–C) An unpaired t test was used to calculate statistical significance (p ≤ 0.05). Data from two studies were pooled; AD→APP KO, n = 8 males, n = 10 females; and WT→APP KO, n = 7 males, n = 7 females.
(E) Spontaneous alternation (Y maze) test. A significantly high POA was observed in the WT→APP KO mice versus the AD→APP KO mice. An unpaired t test was used to calculate statistical significance (p ≤ 0.05). AD→APP KO, n = 8 males, n = 10 females; and WT→APP KO, n = 7 males, n = 7 females.
(F) Contextual fear conditioning test (FC). WT→APP KO mice exhibited high freezing percentages compared to AD→APP KO mice. Due to technical issues, data for this test were collected only from one trial. An unpaired t test was used to calculate statistical significance (p ≤ 0.05). Data for this test are only from the first trial due to issues with equipment at the time of the experiment. AD→APP KO, n = 4 males, n = 4 females; and WT→APP KO, n = 3 males, n = 3 females.
(G and H) RAWM. Both (G) latency time and (H) the total number of errors were measured. WT→APP KO mice showed a significant decrease in the latency time and decreased number of errors when comparing results from test day 1 and test day 5. No significant differences between test day 1 and test day 5 were seen in the AD→APP KO. A paired t test was used to calculate significance (p ≤ 0.05). AD→APP KO, n = 8 males, n = 10 females; and B6/SJL.BM→APP KO, n = 7 males, n = 7 females.