不同泻药致豚鼠结肠黑变病的实验研究

Melanosis of colon induced by different laxatives in guinea pigs: an experimental study

目的探讨结肠黑变病(MC)的发病机制。方法将SPF级豚鼠随机分为4组,分别采取常温水(2 m L)、大黄(1.16 g/kg)、番泻叶(0.46 g/kg)、果导片(15.43 mg/kg)灌胃,在第4周和第8周分别处死半数豚鼠,采用肉眼和黑色素染色法观察各组豚鼠结肠色素沉着情况,采用HE染色法观察各组豚鼠结肠组织病理形态,并采用TUNEL法检测各组豚鼠结肠组织细胞凋亡情况、ELISA法检测各组肿瘤坏死因子(TNF-α)水平。结果灌胃4周、8周后大黄、番泻叶、果导片组豚鼠结肠均发生不同程度黑变(P<0.01),随时间延长结肠黑变程度均加重,但仅番泻叶组灌胃8周与4周结肠黑变程度有统计学差异(P<0.05);大黄、番泻叶、果导片组灌胃4周、8周后结肠组织细胞凋亡OD值,均显著高于正常组(P<0.01),随时间的延长OD值均有所升高,但无统计学差异(P>0.05);大黄组灌胃4周、8周后TNF-α含量均高于正常组(P<0.05),随时间的延长TNF-α含量显著升高(P<0.01)。番泻叶组灌胃4周TNF-α含量与正常组比较无统计学差异(P>0.05),灌胃8周TNF-α含量高于正常组(P<0.05),随时间的延长TNF-α含量显著升高(P<0.01)。果导片组灌胃4周、8周后TNF-α含量与正常组比较均无统计学差异(P>0.05),随时间增延长TNF-α含量有所升高,但无统计学差异(P>0.05)。结论大黄、番泻叶、果导片均可致豚鼠发生MC,MC的发病机制可能与结肠上皮细胞凋亡有关,但与TNF-α水平之间的关系有待进一步深入研究。

Objective To discuss the pathogenesis of melanosis of colon （MC）. Methods SPF guinea pigs were randomly divided into 4 groups ： normal group （ given water, 2 mL n = 8 ） , group of Dahuang （Radix et Rhizoma Rhei, Rhubarb; Dahuang group, 1.16 g/kg n = 16）, group of Fanxieye （Folium Sennae, Senna Leaf, Fanxieye group, 0.46 g/kg n = 16 ） and Phenolphthalein Tablets group （15.43 mg/kg n = 16）, and all groups were intragastrically given corresponding medicinal. The half numbor of guinea pigs was executed on the 4th week and other half were executed on the 8th week. The status of colonic pigmentation of guinea pigs in each group was observed by direct visual observation and melanin staining. The colonic histopathology of guinea pigs in each group was observed by the method of HE staining. The apoptosis of colon tissue was detected by using terminal-deoxynucleoitidyl transferase mediated nick end labeling （TUNEL）, and level of tumor necrosis factor-α（TNF-α） was detected by using enzyme-linked immunosorbent assay （ELISA） in all groups. Results There was MC occurred in varying degrees in Dahuang group, Fanxieye group and Phenolphthalein Tablets group after 4 weeks and 8 weeks （P 〈0.01 ）. MC aggravated along with time increased, however, there was statistical difference in MC severity only between Fanxieye group and normal group after 4 weeks and 8 weeks （ P 〈 0.05 ）. The value of optical density （OD） was significantly higher in Dahuang group, Fanxieye group and Phenolphthalein Tablets group than that in normal group after 4 weeks and 8 weeks （P〈0.01）, and along with time increased, OD value also increased but had no statistical difference （ P 〉 0.05 ）. The level of TNF-α was higher in Dahuang group than that in normal group after 4 weeks and 8 weeks （ P 〈 0. 05 ）, and increased significantly along with time increased （ P 〈 0.01 ）. The level of TNF-a had no statistical difference between Fanxieye group and normal group after 4 weeks （P 〉 0.05 ）, was higher in Fanxieye group than that in normal group after 8 weeks （P 〈 0.05 ）, and increased significantly along with time increased （P 〈 0.01 ）. The level of TNF-ot had no statistical difference between Phenolphthalein Tablets group and normal group after 4 weeks and 8 weeks （P 〉 O. 05 ）, and along with time increased, level of TNF-α also increased but had no statistical difference （P 〉 0.05 ）. Conclusion Dahuang, Fanxieye and Phenolphthalein Tablets all can induce MC in guinea pigs, and the pathogenesis may be related to apoptosis of colonic epithelial cells. But the relationship between MC and level of TNF-α needs further research.