大鼠产后抑郁症动物模型的建立和行为学评估

Postpartum depression animal model in rats and its behavior study

目的建立产后抑郁症动物模型,观察抑郁母鼠产后异常的母性行为,建立产后抑郁症动物模型的评估方案。方法将32只受孕大鼠随机分为3组:地塞米松组(n=10),自受孕第1天起皮下注射生理盐水1 ml/(Kg.d),第15天起,注射地塞米松0.2 mg/(kg.d)至分娩;生理盐水对照组(n=8),孕全程给予生理盐水1 ml/(Kg.d);空白对照组(n=5),自然饲养。母鼠分娩后,观察其对幼崽的关爱行为及自身积极和消极行为,行强迫游泳实验,记录幼崽第1周内的体重增量。结果地塞米松组母鼠与空白对照组和盐水对照组比较,产后对幼崽关爱行为减少(P<0.05),崽鼠生后1周内体重增长低(P<0.01),自身积极活动较少(P<0.05,P<0.01),消极活动较多(P<0.01);在强迫游泳实验中,地塞米松组母鼠挣扎自救行为持续时间短(P<0.01),较早进入不动绝望状态(P<0.01),持续较长时间(P<0.01)。结论孕晚期短期低剂量的地塞米松注射可诱导母鼠出现产后抑郁症状;观察母鼠在强迫游泳实验中的表现及其对幼崽的关爱行为能够对母鼠抑郁行为进行评估。

Objective To establish a postpartum depression animal model, observe the abnormal maternal behavior of depressive dams, and design an assessing procedure. Methods On the first day of pregnancy, 23 female rats were randomly assigned to three groups： dexamethasone group, with ten rats received daily subcutaneous injection of saline 1 ml/（kg＇d） from the first day and then replaced with dexamethasone 0.2 mg/（kg-d） from the 15 th day until delivery on the 22 th day; saline control group, with eight rats received saline vehicle 1 ml/（kg.d） with the same procedure; undisturbed control group, with five rats fed naturally. After parturition, dams＇ maternal care towards offspring as well as their positive and negative motion was carefully recorded, cubs＇ weight gain during the first postnatal week was recorded and then a forced swim test was carried out for each dam. Results Compared with undisturbed control and saline control group, dams received dexamethasone showed less maternal care towards offspring （P〈0.05）, resulting in cubs＇ less weight gain during the first postnatal week （P〈0.01）, besides, those dams performed less positive （P〈0.05, P〈0.01 ） and more negative motion （P〈0.01）. In the forced swim test, dexamethasone dams swam and struggled for shorter time （P〈0.01）, became despaired earlier （P〈0.01） and remained immobile for a longer time （P〈0.01）. Conclusion During later pregnancy, dethamethasone can induce dams into postpartum depression at a low dose by short period administration. Dams＇ maternal care to litters and their performance in forced swim test can be used to assess postpartum depression in further animal model research.