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Fig. 2 | Particle and Fibre Toxicology

Fig. 2

From: Silica nanoparticles induce neurodegeneration-like changes in behavior, neuropathology, and affect synapse through MAPK activation

Fig. 2

Effects of NP on mood and cognition in mice. a Experimental design for NP administration and behavioral tests. Male C57BL/6 N mice (3 months old) were administered PBS or NP (final dosage 8 mg/kg) via intranasal instillation once per day for 81 days. Behaviors were tested according to the plan. Abbreviations: R, rotarod test; OF, open field test; EPM, elevated plus maze test; NOR, novel object recognition test; SI, social interaction test; MWM, Morris water maze test; TST, tail suspension test; FST, forced swimming test. b SI activity (ratio of juvenile helper to empty chamber interaction,Thelper/Tempty) was tested at days 23 (1 month time point, left) and 66 (2 month time point, right) and analyzed with an unpaired Student’s t-test and unpaired non-parametric Mann-Whitney test, respectively. c EPM was used to evaluate anxiety, presented as the ratio of time spent in open arms to closed arms (Topen/Tclose), at days 19 (1 month time point, left) and 62 (2 month time point, right) and analyzed with unpaired Student’s t-tests. The effects of NP exposure on cognition were tested with the NOR (d, 1 month; e, 2 months) and the MWM (f and g, training and probe phase at 1 month; h and i, training and probe phase at 2 months). For the NOR, memory is demonstrated by the ratio of time interacting with new object to that interacting with the old object (Tnew/Told). Data from 1 month and 2 months were analyzed by unpaired Student’s t-tests, and unpaired Mann-Whitney test, respectively. For the MWM, the learning curve was plotted using the average escape latency per day in the training phase and was analyzed using a repeated measures two-way ANOVA. Spatial memory, represented by the platform-crossing time during the probe phase, was analyzed using unpaired Mann-Whitney tests. * p < 0.05, **** p < 0.0001, compared to controls. n = 8, 12, or 20, indicates that each group has the same number of mice, while n = 17–20 means that all groups included 20 mice except the 1 month control group which only had 17 as 3 videos were accidentally lost

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