环境丰容对SD大鼠行为和肾上腺皮质激素的影响研究

Effect of environmental enrichment on behavior and cortin levels in SD rats

目的研究评价不同的环境丰容方案对大鼠行为和肾上腺皮质激素的影响。方法45只6周龄雄性SD大鼠,随机分为4组,单笼组9只,单笼饲养。新奇组、丰容组和对照组各12只,3只/笼饲养。新奇组提供由筑巢材料、遮蔽物、磨牙棒3种丰容材料组成的复合丰容方案,并每周更换不同的组合方案。丰容组只提供1种丰容材料,丰容材料在更换垫料时根据损耗情况及时更新。对照组和单笼组不提供丰容材料。连续丰容9周,采用瞬时扫描法记录大鼠行为时间分配,利用ELISA试剂盒检测血清和尿中促肾上腺皮质激素(ACTH)及皮质酮(CORT)浓度。结果新奇组探究行为显著高于其他组,单笼组不活跃行为增加,单纯性活动行为极显著增加,丰容组和对照组无显著差异。血清中ACTH和CORT的浓度各组间无显著性差异。尿液中ACTH和CORT浓度呈现新奇组>单笼组>对照组>丰容组的趋势,但除新奇组ACTH极显著高于其他三组,其他差异不显著。结论单笼饲养抑制SD大鼠行为表达,是对动物福利的损害,而复合新奇的丰容方案虽增加大鼠探究行为等积极行为,但同时对肾上腺皮质激素也有影响,实际应用时应根据具体饲养条件选择简单实用的环境丰容材料和方案。

Objective This study focused on the effects of different enrichment designs on behavior and cortin levels in male SD rats.Methods Forty-five 6-week-old male specific pathogen free SD rats were randomly divided into four groups.The single cage group had nine rats and the other three groups each had 12 rats.The novelty group was housed in a composite environmental enrichment scheme composed of nesting material,shelter,grinding rods,and a new scheme was provided every week.The environmental enrichment group provided one kind of material every week.The control group and the single cage group did not receive enrichment.The experiment lasted 9 weeks.Behavior was sampled using instantaneous scanning sampling method.Serum and urine adrenocorticotropic hormone(ACTH)and corticosterone(CORT)levels were measured.Results Novelty group rats exhibited more exploring behaviors than rats in the other groups.Rats of the single cage group increased their inactive behavior.No significant differences were found among groups in the serum levels of ACTH or CORT.However,in urine,the concentration of ACTH and CORT showed the following trend:novel group>single cage group>control group>environmental enrichment group.Conclusions Single cage housing inhibits the expression of behaviors in SD rats,which is detrimental to their welfare.However,the complex novel enrichment program increased positive behaviors,such as exploration behavior and also has an effect on adrenocortical hormones.In practice,simple and practical environmental enrichment materials and schemes should be selected according to specific housing conditions.