夜香树甾体皂苷抗人肝癌裸鼠移植瘤的研究

目的: 观察夜香树甾体皂苷(SSCN)对肝癌HepG2移植瘤的抑制作用,并探讨其抑瘤的可能机制。方法: 从夜香树叶中提取并鉴定SSCN;建立BALB/c裸鼠HepG2肝癌模型,建模成功后将荷人肝癌裸鼠随机分为5组:生理盐水组(NS)、沙利度胺组(TLD 200 mg·kg^-1),SSCN低,中,高组(4,6,8 mg·kg^-1,ip, 隔日1次,连续30 d),观察SSCN的肿瘤抑制作用。治疗期间测量皮下移植瘤的长径和短径;30 d后处死裸鼠,剖取肿瘤,行常规制片,HE染色,镜下观察肿瘤病变;免疫组化染色,观察并检测移植瘤中增殖细胞核抗原PCNA和Ki-67蛋白的表达。结果: TLD组裸鼠ip对肝癌HepG2 BALB/c裸鼠相对肿瘤增殖率为42.19%,SSCN 4,6,8 mg·kg^-1的增殖率分别为48.26%,42.94%,41.57%,随着剂量的增高其相对肿瘤增殖率逐渐下降,SSCN抑制肿瘤生长的作用存在剂量依赖性。镜下观察,SSCN高剂量组见到大量坏死细胞外,部分肿瘤细胞体积较小,细胞核浓染。NS组荷瘤小鼠的肿瘤细胞中PCNA和Ki-67蛋白的表达率明显增高;而与NS组比较,TLD组和SSCN高剂量组PCNA和Ki-67蛋白的表达显著下降(P<0.05)。结论: 夜香树甾体皂苷体内对BALB/c小鼠肝癌移植瘤有一定的抑制作用,其作用机制可能是通过下调PCNA和Ki-67基因蛋白的表达,从而抑制肿瘤细胞的增殖。

In Vivo Antitumor Effects of Steroidal Saponins from Cestrum nocturnum Linn. (SSCN) on Human Hepatocellular Carcinoma Xenografts in Nude Mice

Objective: To investigate the antitumor effects and it's mechanism of steroidal saponins from Cestrum nocturnum,Linn (SSCN) on human hepatocellular carcinoma xenografts in nude mice in vivo. Method: SSCN was separated and identified their structure. The animal model of human hepatocellular carcinoma xenografts was established by subcutaneous inoculation of hepatocellular carcinoma HepG2 cells into nude mice. The mice were randomly divided into five groups:NS group, thalidomide (TLD) group, and SSCN 4, 6, 8 mg·kg^-1·d^-1group ip, every the other day for 30 days. During treatment, tumor size was measured. The mice were killed 30 days later to observe tumor morphology. The tumor samples were observed and analyzed using HE staining and immunohistochemical staining. The protein expression of proliferating cell necliar antigen(PCNA) and Ki-67 in transplantation tumor was detected. Result: The relative proliferation rate in TLD group in tumor nude mice was 42.19%. The relative proliferation rate in SSCN high, middle and low dose in tumor nude mice was 48.26%,42.94%,41.57% accordingly. Along with the increase of the dose of SSCN the relative tumor proliferation rate decrease gradually, explaining the inhibition of tumor growth by SSCN in dose dependence manner. A large number of necrotic cells in tumor tissue sections could be viewed in SSCN 8 mg·kg^-1 group. Some tumor cells were smaller, and nuclear staining was dense. The protein expression of proliferating cell nuclear antigen (PCNA) and Ki-67 in transplantation tumor was markedly higher. Compared with the NS group, the protein expression of PCNA and Ki-67 was markedly lower in TLD group and SSCN 8 mg·kg^-1 group(P<0.05). Conclusion: SSCN show certain inhibitory effect on human hepatocellular carcinoma xenografts in nude mice in vivo. The anti-tumor mechanism is probably related to down-regulation of the protein expression of PCNA and Ki-67 gene, thus inhibiting tumor cell proliferation.