肋间神经切断对大鼠乳腺增生的影响

Effects of intercostal nerve transection on hyperplasia of mammary glands in rats

摘要:

目的：观察切断右侧第7、8肋间神经对大鼠乳腺增生（hyperplasia of mammary gland，HMG）的影响。方法：将 60 只 SD 大鼠随机分为正常组、模型组、肋间神经切断组和卵巢切除组共 4 组。使用苯甲酸雌二醇联合黄体酮注射液肌注的方法建立大鼠HMG模型。术后2、4、6 周测量各组大鼠乳头直径、高度及乳腺组织形态变化及Ki-67的表达，乳腺组织雌激素受体（estro－gen receptor，ER）和孕激素受体（progestogen receptor，PR）的 mRNA表达水平和蛋白表达及增殖细胞核抗原（proliferating cell nuclear antigen，PCNA）的蛋白表达。结果：手术后2、4、6周，各时间点肋间神经切断组大鼠右侧第3个乳头直径、高度均低于模型组，差异有统计学意义（P<0.05）。手术后各时间点乳腺组织病理改变比较，肋间神经切断组乳腺导管上皮细胞层数、小叶腺泡数减少程度，腺泡腔、导管扩张减轻程度均低于模型组，差异有统计学差异（P<0.05）。免疫组化检测发现 Ki-67 各组表达均为阴性。PCR显示肋间神经切断组乳腺组织的 ER、PR 的mRNA 表达均低于模型组（P<0.05）。Western blot 结果显示肋间神经切断组乳腺组织的ER、PR和PCNA蛋白表达均低于模型组（P<0.05）。结论：切断肋间神经减轻大鼠HMG的乳腺组织病理改变，减少乳腺组织中ER和PR的mRNA和蛋白表达水平，降低PCNA的蛋白表达水平。

Abstract:

Objective：To study the effects of cutting off the seventh and the eighth intercostal nerve in the right side on hyperplasia of mammary gland（HMG） in SD rats. Methods：Totally 60 SD rats were randomly divided into 4 groups：normal group，model group，in－tercostal nerve transection group and ovariectomized group. Intramuscular injection of estradiol benzoate combinng with progesterone was provided to establish a rat model HMG. Diameter and height of the third nipple by right side in each group were measured at 2，4，6 weeks，respectively. Moreover，morphological changes and Ki-67 expression of the breast tissues were observed. mRNA levels and protein levels of estradiol receptor（ER） and progestogen receptor（PR） in breast tissues were measured by real time PCR and West－ern blot; protein levels of proliferating cell nuclear antigen（PCNA） were measured by Western blot respectively. Results：Diameter and height of the third nipple at the right side were measured. Diameter and height were lower in intercostal nerve transection group than in model group（P<0.05）. Layers of epithelial cell，numbers of acinus，diameter of acinus and diameter of duct of mammary gland were markedly reduced in intercostal nerve transection group than in model group（P<0.05）. In addition，mRNA and protein levels of ER and PR and the protein levels of PCNA in breast tissues were lower in intercostal nerve transection group than in model group（P<0.05）. Conclusions：Intercostal nerve transection could reduce pathological changes of HMG and reduce mRNA and protein ex－pressions of ER and PR as well as protein expressions of PCNA in rat mammary gland.