目的:调节性T细胞(Regulatory T cells,Treg)被认为能够抑制抗肿瘤免疫反应,从而促进肿瘤生长。环磷酰胺(Cyclophosphamide,CTX)是个常规化疗药物,现在更多的注意力集中在其小剂量应用时可以删除Treg。了解小剂量环磷酰胺联合白细胞介素-2(Interleukin-2,IL-2)对4T1Balb/c乳腺癌荷瘤小鼠调节性T细胞的影响及其抗肿瘤效果。方法:通过皮下接种4T1乳腺癌细胞建立乳腺癌Balb/c荷瘤小鼠模型;20只荷瘤小鼠随机分为IL-2+NS组、PBS+CTX组、IL-2+CTX组及PBS+NS组,在种瘤第10天开始对荷瘤小鼠分别经腹腔按方案给药。在种瘤后第16天人道处死小鼠,采用流式细胞术检测小鼠脾脏中CD4+CD25+调节性T细胞数量,应用ELISA法检测血清干扰素-γ浓度,电子称称量肿瘤重量。结果:与对照组相比,在应用IL-2后,荷瘤小鼠脾脏CD4+CD25+/CD4+比值增加,在应用IL-2的同时使用小剂量CTX可减少CD4+CD25+/CD4+的比值;单次及联合用药均可提高血清INF-γ浓度;联合用药可减少肿瘤重量。结论:小剂量CTX可以减少由使用IL-2所增加的Treg数量,促进抗肿瘤免疫,提高IL-2的抗瘤效果,从而抑制肿瘤生长。该研究可能为乳腺癌的临床治疗提供一种有效的方法。
In the present experiment, Pavlovian fear conditioning was adopted to study the effects of different early rearing environments on fear conditioning in adult rats. Weaned rats were reared in three manipulable environments （enriched, social and isolated conditions）. After 8 weeks, fear conditioning （characterized by percentage of freezing） was observed and analyzed, and rats＇ weight, locomoter activity and foot-shock sensitivity were operated too. The results showed that： （1） Compared with control group, the level of conditioned fear was significantly increased in enriched group, but significantly decreased in isolated group; （2） Enriched and isolated conditions influenced rat＇s weight significantly; （3） Different rearing conditions have no effect on locomoter activity and foot-shock sensitivity. These results indicated that early enriched condition could improve the tone-evoked fear conditioning response, while isolated condition impaired the response.
