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Comparison of Neurological Function in Males and Females from Two Substrains of C57BL/6 Mice.

Ashworth A, Bardgett ME, Fowler J, Garber H, Griffith M, Curran CP - Toxics (2014)

Bottom Line: However, B6N females had significantly shorter path lengths in the reversal and shifted-reduced phases.In the fear conditioning test, B6N males had a significantly longer time freezing in the new context compared with B6J males, but no significant differences were found in contextual or cued tests.Both factors (sex and substrain) must be taken into account when designing developmental neurotoxicology studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Dr, Highland Heights, KY 41099, USA.

ABSTRACT

The C57BL/6 (B6) mouse is the background strain most frequently used for genetically-modified mice. Previous studies have found significant behavioral and genetic differences between the B6J (The Jackson Laboratory) and B6N substrains (National Institutes of Health); however, most studies employed only male mice. We performed a comprehensive battery of motor function and learning and memory tests on male and female mice from both substrains. The B6N male mice had greater improvement in the rotarod test. In contrast, B6J female mice had longer latencies to falling from the rotarod. In the Morris water maze (MWM), B6J males had significantly shorter latencies to finding the hidden platform. However, B6N females had significantly shorter path lengths in the reversal and shifted-reduced phases. In open field locomotor activity, B6J males had higher activity levels, whereas B6N females took longer to habituate. In the fear conditioning test, B6N males had a significantly longer time freezing in the new context compared with B6J males, but no significant differences were found in contextual or cued tests. In summary, our findings demonstrate the importance of testing both males and females in neurobehavioral studies. Both factors (sex and substrain) must be taken into account when designing developmental neurotoxicology studies.

No MeSH data available.


Related in: MedlinePlus

(A–D) Morris water maze latency: males. B6J males had shorter latencies to escaping. Swim speed was significantly different in all three phases of hidden platform testing. †p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001. Data are the least square means ± S.E.M.
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Figure 4: (A–D) Morris water maze latency: males. B6J males had shorter latencies to escaping. Swim speed was significantly different in all three phases of hidden platform testing. †p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001. Data are the least square means ± S.E.M.

Mentions: There were no significant differences in the cued platform phase for male mice (data not shown). We found significant differences in all three phases of hidden platform testing (Figure 4A–C). There was a main effect of day in all three phases (p < 0.001) and a gene × day interaction. B6J males had significantly shorter latencies on Day 5 of acquisition testing (F1,182 = 4.29; p < 0.05), a trend toward significance on Day 6 of reversal testing (F1,148 = 2.76; p < 0.1) and significantly shorter latencies on Days 4 (F1,143 = 3.77; p < 0.05) and 5 (F1,143 = 7.29; p < 0.01) of shift-reduced testing after correcting for speed as a covariate. B6N males had shorter path lengths in the shift-reduced phase (Figure 5A–C). We also found significant differences in swim speed, with B6N males swimming more slowly than B6J males (Figure 4D); however, latency differences remained significant even after correcting for this covariate. No differences were found in the probe trials for males (Figure 5D).


Comparison of Neurological Function in Males and Females from Two Substrains of C57BL/6 Mice.

Ashworth A, Bardgett ME, Fowler J, Garber H, Griffith M, Curran CP - Toxics (2014)

(A–D) Morris water maze latency: males. B6J males had shorter latencies to escaping. Swim speed was significantly different in all three phases of hidden platform testing. †p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001. Data are the least square means ± S.E.M.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829364&req=5

Figure 4: (A–D) Morris water maze latency: males. B6J males had shorter latencies to escaping. Swim speed was significantly different in all three phases of hidden platform testing. †p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001. Data are the least square means ± S.E.M.
Mentions: There were no significant differences in the cued platform phase for male mice (data not shown). We found significant differences in all three phases of hidden platform testing (Figure 4A–C). There was a main effect of day in all three phases (p < 0.001) and a gene × day interaction. B6J males had significantly shorter latencies on Day 5 of acquisition testing (F1,182 = 4.29; p < 0.05), a trend toward significance on Day 6 of reversal testing (F1,148 = 2.76; p < 0.1) and significantly shorter latencies on Days 4 (F1,143 = 3.77; p < 0.05) and 5 (F1,143 = 7.29; p < 0.01) of shift-reduced testing after correcting for speed as a covariate. B6N males had shorter path lengths in the shift-reduced phase (Figure 5A–C). We also found significant differences in swim speed, with B6N males swimming more slowly than B6J males (Figure 4D); however, latency differences remained significant even after correcting for this covariate. No differences were found in the probe trials for males (Figure 5D).

Bottom Line: However, B6N females had significantly shorter path lengths in the reversal and shifted-reduced phases.In the fear conditioning test, B6N males had a significantly longer time freezing in the new context compared with B6J males, but no significant differences were found in contextual or cued tests.Both factors (sex and substrain) must be taken into account when designing developmental neurotoxicology studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Dr, Highland Heights, KY 41099, USA.

ABSTRACT

The C57BL/6 (B6) mouse is the background strain most frequently used for genetically-modified mice. Previous studies have found significant behavioral and genetic differences between the B6J (The Jackson Laboratory) and B6N substrains (National Institutes of Health); however, most studies employed only male mice. We performed a comprehensive battery of motor function and learning and memory tests on male and female mice from both substrains. The B6N male mice had greater improvement in the rotarod test. In contrast, B6J female mice had longer latencies to falling from the rotarod. In the Morris water maze (MWM), B6J males had significantly shorter latencies to finding the hidden platform. However, B6N females had significantly shorter path lengths in the reversal and shifted-reduced phases. In open field locomotor activity, B6J males had higher activity levels, whereas B6N females took longer to habituate. In the fear conditioning test, B6N males had a significantly longer time freezing in the new context compared with B6J males, but no significant differences were found in contextual or cued tests. In summary, our findings demonstrate the importance of testing both males and females in neurobehavioral studies. Both factors (sex and substrain) must be taken into account when designing developmental neurotoxicology studies.

No MeSH data available.


Related in: MedlinePlus