Fig 1.
A timeline of the experiments.
A–behavioral tests, B–blood smears (bottom) and brain immunohistochemistry (top), HT—animals with high excitability threshold, LT–animals with low excitability threshold.
Fig 2.
Interstrain differences in the volage threshold in LT and HT rat strains.
HT—animals with high excitability threshold, LT–animals with low excitability threshold, n = 32–34 per group; the graphs represent the medians, quartile boundaries, and maximum and minimum values of the analyzed data; ** p≤ .01 (Mann-Whitney test).
Fig 3.
Effect of long-term stress on open field activity of HT and LT rats.
The number of unsupported rears (A), number of crossed sectors (B), time of immobility (C), time of grooming (D); HT control—animals with high excitability threshold, control group, HT stress—animals with high excitability threshold, stressed group, LT control–animals with low excitability threshold, control group, LT stress–animals with low excitability threshold, stressed animals, n = 4–12 per group; the graphs represent the medians, quartile boundaries, and maximum and minimum values of the analyzed data; ** p≤ .01 (Mann-Whitney test).
Fig 4.
Effect of long-term stress on elevated plus maze activity of HT and LT rats.
Time spent in open arms (A), time spent in closed arms (B), number of visits to the center of the field (C); HT control—animals with high excitability threshold, control group, HT stress—animals with high excitability threshold, stressed group, LT control–animals with low excitability threshold, control group, LT stress–animals with low excitability threshold, stressed animals, n = 5–12 per group; the graphs represent the medians, quartile boundaries, and maximum and minimum values of the analyzed data; ** p≤ .01 (Mann-Whitney test).
Fig 5.
Effect of long-term stress on neutrophil:lymphocyte ratio (N:L ratio) in LT and HT rats.
Intertrain comparison of intact rats (A), effect of stress on N:L ratio in HT strain (B), effect of stress on N:L ratio in LT strain (C), dynamics of stress related changes in N:L ratio in HT (D) and in LT rats (E). LT control–low excitability threshold, control group, LT stress–low excitability threshold, stressed animals; HT control–high excitability threshold, control group, HT stress–high excitability threshold, stressed animals; n = 9–11 per group; bars represent medians and interquartile range; B—** p≤ .01 (Mann-Whitney test), D-F **—p≤ .01 (Wilcoxon test with FDR correction).
Fig 6.
Neutrophils (white arrows) and lymphocytes (black arrows) in LT group before stress (right) and LT group 7 days after stress (left).
Fig 7.
Interstrain differences in the number of Iba1+ cells in different hippocampal areas.
The number of Iba1+ cells in the CA1, CA3 and DG areas of the hippocampus; n = 5–12 per group; bars represent medians; *p≤0,05 Mann-Whitney U test.
Fig 8.
Effect of long-term stress on the number of microglial cells in the hippocampus in HT and LT rats.
(A) The number of Iba1+ cells in the CA1 area of the hippocampus, (B)–in CA3 area and (C)–in the dentate gyrus (DG); n = 5–12 per group; bars represent medians and interquartile range; **p≤0,01 Mann-Whitney U test.
Fig 9.
Iba1+ cells in the DG of LT stressed group (left) and LT control group (right).