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目的研究慢性轻度应激对DMBA诱发性乳腺癌发生发展的影响及可能的机制。方法 24只雌性SD大鼠随机分为空白对照组、DMBA模型组、DMBA应激组3个组。除空白对照组外,每只大鼠均以致癌剂DMBA诱导(剂量10mg/100g,两次,间隔1周)乳腺癌。诱导d2开始,应激组进行轻度慢性不可预知性应激,每周触诊所有大鼠乳腺肿瘤发生情况并记录体重变化。13周后处死动物,观察各组大鼠乳腺肿瘤的发病率并检测血清中皮质酮(CORT)和热休克蛋白70(Hsp70)含量。结果 DMBA应激组大鼠乳腺肿瘤发生率、肿瘤数量和肿瘤平均体积均明显高于模型对照组(P﹤0.05);同时,应激大鼠血清CORT和Hsp70明显高于模型对照组(P﹤0.05)。结论轻度慢性应激能明显促进DMBA诱导乳腺肿瘤的发生及恶化,可能与其体内CORT和Hsp70含量升高密切相关。
Objective To investigate the effect of chronic mild stress on the occurrence and development of DMBA-induced breast cancer and its possible mechanism. Methods Twenty-four female Sprague-Dawley rats were randomly divided into three groups: blank control group, DMBA model group and DMBA stress group. Except for the blank control group, each rat was induced with DMBA, a carcinogen, at a dose of 10 mg / 100 g twice a week for 1 week. At the beginning of induction of d2, mild chronic unpredictable stress was observed in the stress group. All rats were palpated weekly for breast tumor occurrence and body weight changes were recorded. After 13 weeks, the animals were sacrificed and the incidence of breast tumors in each group was observed. The levels of corticosterone (CORT) and heat shock protein 70 (Hsp70) in serum were also measured. Results The incidence of breast cancer, the number of tumors and the average volume of tumors in DMBA stress group were significantly higher than those in model control group (P <0.05). Meanwhile, the levels of CORT and Hsp70 in stress rats were significantly higher than those in model control group (P < 0.05). Conclusion Mild chronic stress can significantly promote the occurrence and deterioration of breast cancer induced by DMBA, which may be closely related to the increase of CORT and Hsp70 in vivo.