Vulnerability or resilience of motopsin knockout mice to maternal separation stress depending on adulthood behaviors

Figures & data

Figure 1 Schematic illustration of the experimental schedule.

Notes: Subjects were applied with a maternal separation paradigm between P2 and P14 and weaned at P27. Before behavioral tests, they were individually housed for 2 weeks. Brains were prepared 3 hours after the three-chamber test.
Abbreviation: P, postnatal day.

Figure 2 Rearing condition affected anxiety-like behavior in the open field test.

Notes: (A) There is no significant difference in total path length among the experimental groups. (B) MS-WT mice exhibited a decreased duration in the center area compared with AFR-WT mice. ^aP<0.05 vs AFR of the same genotype; ^*P<0.05.
Abbreviations: AFR, animal facility rearing; KO, knockout; MS, maternal separation; sec, seconds; WT, wild type.

Figure 3 The MS paradigm decreased the desire to investigate a novel object.

Notes: (A) A novel and a familiar object was composed of five black cuboctahedrons and four arms. They were presented to a subject mouse for 5 minutes. (B) The total duration to investigate the objects was not significantly affected by rearing condition or genotype. (C) The novel object recognition index was reduced in MS mice. ^*P<0.05.
Abbreviations: AFR, animal facility rearing; KO, knockout; MS, maternal separation; sec, seconds; WT, wild type.

Figure 4 Rearing condition and genotype affected perseverative behaviors.

Notes: (A) MS-KO mice buried marbles in a time-dependent manner. Other groups buried most of the marbles within the first 10 minutes and did not bury additional marbles afterward. (B) At 10 minutes, WT mice had buried more marbles than KO mice. (C) The number of buried marbles at 20 minutes. (D) WT mice tended to bury more marbles than KO mice, but this was not significant. ^#P<0.05 vs WT mice of the same rearing condition; ^*P<0.05.
Abbreviations: AFR, animal facility rearing; KO, knockout; min, minutes; MS, maternal separation; WT, wild type.

Figure 5 Neither rearing condition nor genotype affected social behaviors in the resident–intruder test.

Notes: (A) Total contact time. (B) The duration of active behaviors (chasing and anogenital sniffing). (C) The duration of passive behaviors (being chased, being anogenitally sniffed). (D) The duration of aggressive behaviors (biting, kicking). (E) The latency to the first contact.
Abbreviations: AFR, animal facility rearing; KO, knockout; MS, maternal separation; sec, seconds; WT, wild type.

Figure 6 Rearing condition and genotype affected anxiety-like behavior in the elevated plus maze test.

Notes: (A) Total arm entries. There was no significant effect or interaction of genotype and rearing condition. (B) The number of open arm entries. The effects of MS were opposite between motopsin WT and KO mice. (C) The duration spent on the open arm. ^#P<0.05 vs WT mice of the same rearing condition.
Abbreviations: AFR, animal facility rearing; KO, knockout; MS, maternal separation; sec, seconds; WT, wild type.

Figure 7 Rearing condition and genotype affected social behaviors in the three-chamber test.

Notes: (A) Cumulative duration to investigate the empty or unfamiliar mouse-containing wire cage. (B) Motopsin deficiency reduced the ratio of sniffing the animal cage under AFR conditions, whereas MS increased it in only motopsin KO mice. (C) The MS paradigm increased the cumulative duration to sniff a cage containing a familiar or unfamiliar mouse by motopsin KO mice. (D) The ratio of investigating an unfamiliar mouse was not affected by rearing condition or genotype. ^aP<0.05 vs AFR of the same genotype; ^#P<0.05 vs WT mice of the same rearing condition.
Abbreviations: AFR, animal facility rearing; KO, knockout; MS, maternal separation; sec, seconds; WT, wild type.

Figure 8 The immunoreactivity of cFos in the mPFC.

Notes: (A) AFR-WT. PrL and IL cortices are boxed. (B) AFR-KO. (C) MS-WT. (D) MS-KO. Bar, 200 µm.
Abbreviations: AFR, animal facility rearing; cc, corpus callosum; IL, infralimbic; KO, knockout; mPFC, medial prefrontal cortex; MS, maternal separation; PrL, prelimbic; WT, wild type.

Figure 9 Rearing condition and genotype affected the number of cFos-positive cells in the mPFC after the three-chamber test.

Notes: (A) Anterior cingulate cortex. (B) Prelimbic cortex. (C) Infralimbic cortex. The number of cFos-positive cells was counted in 400×400 µm². ^aP<0.05 vs AFR of the same genotype; ^#P<0.05 vs WT mice of the same rearing condition; ^**P<0.01.
Abbreviations: AFR, animal facility rearing; KO, knockout; mPFC, medial prefrontal cortex; MS, maternal separation; WT, wild type.

Table 1 Summary of the effects of rearing condition and motopsin deficiency on behaviors and PFC

	Wild type		Motopsin KO		Significance of the effect
	AFR	MS	AFR	MS	Rearing	Genotype	Rearing *genotype
Open field
Duration in the center					*	–	–
Elevate plus maze
Open arm entry					–	–	*
Open arm duration					–	–	–
Marble burying
No of buried marbles					–	*	–
Novel object recognition
Novel object recognition index					*	–	–
Resident-intruder
Duration of active behavior					–	–	–
3 Chamber test
Ratio of sniffing an animal cage					–	–	*
Ratio of sniffing a novel mouse					–	–	–
cFos IR
AC					–	–	–
PrL					–	**	–
IL					–	–	*

Notes:

* P<0.05;

** P<0.01; “–” indicates not significant.

Abbreviations: AC, anterior cingulate cortex; AFR, animal facility rearing; IL, infralimbic; IR, immunoreactivity; KO, knockout; MS, maternal separation; PFC, prefrontal cortex; PrL, prelimbic.