Effects of tryptophan hydroxylase 2 gene knockout on adolescent social play and adult aggressive and homosexual behaviors in male rats
10.3969/j.issn.1671-7856.2025.07.007
- VernacularTitle:色氨酸羟化酶2基因敲除对雄性大鼠青春期社交玩耍行为及成年期攻击行为和同性性行为的影响
- Author:
Yao WU
1
;
Pu FAN
1
Author Information
1. 中国医学科学院基础医学研究所北京协和医学院基础学院生理系重大疾病共性机制研究全国重点实验室,北京 100005
- Publication Type:Journal Article
- Keywords:
ethology;
social play behavior;
aggressive behavior;
Tph2 knockout male rat;
5-HT
- From:
Chinese Journal of Comparative Medicine
2025;35(7):72-83
- CountryChina
- Language:Chinese
-
Abstract:
Objective To examine the effects of tryptophan hydroxylase 2(Tph2)gene knockout on social play behavior during adolescence and on aggressive behavior in adult male rats,in order to elucidate the role of central 5-hydroxytrypatamine(5-HT)synthesis deficits in social behavior during postnatal development.Methods Male Tph2-knockout(Tph2KO)and wild-type(WT)rats were used in this study.Locomotor activity and anxiety levels during adolescence were evaluated after 4 weeks of age using an open-field test and adolescent social play behavior was assessed at 5 and 6 weeks of age using the adolescent social-interaction test.Locomotor activity and anxiety levels during adulthood were evaluated at 8 weeks of age by open-field test,and adult aggressive behavior was assessed at 10 and 11 weeks of age using the resident-intruder test.Results Adolescent Tph2KO male rats exhibited a significantly shorter total travel distance in the open-field test compared with WT male rats(P＜0.05),but there was no significant difference in central zone exploration time or central zone entries between the two groups(P＞0.05).Adolescent Tph2KO rats also displayed significantly increased social play behavior(P＜0.05)and reduced neutral social behaviors(P＜0.01)in the social-interaction test compared with WT controls,but there was no significant difference in overall social behaviors(P＞0.05).Adult Tph2KO male rats exhibited a significantly reduced total travel distance(P＜0.05),a trend towards decreased central zone exploration time(P=0.100),and significantly fewer central zone entries(P＜0.05)in the open-field test compared with WT rats.There were no significant differences in overall social behavior,aggressive behavior,or neutral social behaviors in the resident-intruder test between the two genotypes(P＞0.05).Notably,Tph2KO rats exhibited increased same-sex mounting behavior during both adolescence and adulthood(P＜0.05,P=0.076,respectively).Conclusions Tph2 gene knockout significantly increased social play behavior during adolescence and elevated same-sex mounting behavior during adolescence and adulthood in male rats,but had no significant effect on adult aggressive behavior.These findings suggest that central 5-HT synthesis deficiency selectively modulates adolescent social behavior and impacts same-sex mounting behavior across developmental stages.
