目的：探讨自然衰老下，雌雄小鼠运动功能、感觉功能、认知功能及精细行为的变化。方法：3月龄和 21月龄C57BL/6J小鼠，分别进行运动功能（旷场测试、转棒测试、平衡木实验及步态实验）、感觉功能（Von Frey测试）、认知功能测试（新物体识别测试）及家笼精细行为分析，借此比较自然衰老对雌雄小鼠行为的 影响。结果：在运动功能检测中，与同性别年轻小鼠相比，雌性老年小鼠在旷场中运动距离和运动速度显 著下降（P＜0.05），而雄性老年小鼠无显著改变。在转棒实验中，雌雄老年小鼠的运动平衡性均显著下降 （P＜0.01）。在平衡木实验中，老年小鼠运动平衡性、协调性下降，且老年雄性小鼠下降更加显著（P＜ 0.0001）。在步态实验中，雌雄老年小鼠步态对称性均下降（P＜0.001）。感觉功能方面，雌雄老年小鼠的痛 觉阈值均显著高于同性别年轻小鼠（P＜0.0001），对伤害性刺激反应减弱。认知功能方面，雌雄老年小鼠 失去年轻小鼠所具有的对新物体的探索偏好。家笼内精细行为测试结果显示，相较于同性别年轻小鼠，雌 性老年小鼠自主运动行为和探索行为分别下降9.14%和38.05%，自我照顾行为增加15.52%；雄性老年小鼠 自主运动行为和探索行为分别下降46.50%和9.59%，自我照顾行为增加2.36%。相较于雄性小鼠，雌性小 鼠整体的探索行为和自主运动行为时间占比更多，自我照顾行为更少。结论：小鼠随自然衰老运动和感觉 功能及认知功能衰退，并表现出一定的性别依赖性。

To investigate the changes in motor function, sensory function, cognitive function, and fine behavior in male and female mice during natural aging. Methods: C57BL/6J mice aged 3 months and 21 months were subjected to assessments of motor function (open-field test, rotarod test, balance beam test, and gait analysis), sensory function (Von Frey test), cognitive function (novel object recognition test), and fine behavior analysis in home cages to compare the effects of natural aging on the behavior of male and female mice. Results: In motor function tests, compared with younger mice of the same sex, elderly female mice exhibited a significant decrease in both the distance traveled and movement speed in the open field (P<0.05), while no significant changes were observed in elderly male mice. In the rotarod test, both elderly male and female mice showed a significant decline in motor balance (P<0.01). In the balance beam test, the motor balance and coordination of elderly mice deteriorated, with a more pronounced decline in elderly male mice (P< 0.0001). In the gait analysis, both elderly male and female mice demonstrated a reduction in gait symmetry (P< 0.001). Regarding sensory function, the pain thresholds of both elderly male and female mice were significantly higher than those of younger mice of the same sex (P<0.0001), indicating a diminished response to noxious stimuli. In terms of cognitive function, elderly male and female mice lost the preference for exploring novel objects that was observed in younger mice. The results of fine behavior tests in home cages revealed that, compared with younger mice of the same sex, elderly female mice showed a 9.14% decrease in spontaneous motor behavior and a 38.05% decrease in exploratory behavior, while self-care behavior increased by 15.52%. In elderly male mice, spontaneous motor behavior and exploratory behavior decreased by 46.50% and 9.59%, respectively, while self-care behavior increased by 2.36% . Compared with male mice, female mice spent a greater proportion of time on exploratory and spontaneous motor behaviors and engaged in less self-care behavior overall. Conclusion: As mice age naturally, their motor, sensory, and cognitive functions decline, exhibiting certain sex-dependent characteristics.