木瓜提取物对脂肪性肝纤维化的预防保护作用及机制研究

Protective Effects and Mechanism of Total Extracts of Papaya on Fatty Liver Fibrosis in Mice

目的观察木瓜提取物对高脂饮食联合腹腔注射猪血清致脂肪性肝纤维化的预防保护作用,并初步探讨其作用机制。方法取雌雄各半BABL/C小鼠48只,随机分成4组,每组12只,即正常对照组,模型组,木瓜提取物低(100 mg·kg-1)、高剂量组(300 mg·kg-1)。除正常对照组给予普通饲料外,其余各组均给予高脂饲料造模,同时木瓜提取物低、高剂量组分别给予100,300 mg·kg-1的木瓜提取物灌胃,持续10周;除正常对照组小鼠外,其余各组小鼠在第5周腹腔注射猪血清,持续3周。观察并记录上述各组小鼠造模前后体质量变化、行为和形态变化。苏木精-伊红(HE)、Masson染色,光镜下观察肝组织炎症及肝纤维化情况;用RT-PCR法检测RNA依赖的蛋白激酶样内质网激酶(PERK),肌醇需求酶1(IRE-1),转录因子6(ATF6),真核起始转录因子2α亚单位(e IF2α),组织型金属蛋白酶-1(TIMP-1),α-平滑肌肌动蛋白(α-SMA),胶原蛋白1型(COL 1A1);用Western Blot法检测葡萄糖调节蛋白78(GRP78),肿瘤坏死因子-α(TNF-α),白细胞介素-1β(IL-1β),胶原蛋白1型(COL 1A1)。结果通过肝脏外观、HE和Masson染色后观察,与模型组比较,木瓜提取物低、高剂量组的小鼠肝脏损伤和纤维化程度明显改善,肝组织的PERK、IRE-1、ATF6、e IF2α、TIMP-1、α-SMA、COL 1A1的m RNA表达显著降低(P<0.05),GRP78、TNF-α、IL-1β、COL 1A1的蛋白表达显著降低(P<0.05)。结论木瓜提取物对脂肪性肝纤维化有较好的预防保护作用,其机制可能与对抗内质网应激(ERS)偶联炎症反应有关。

Objective To study the protective effects and possible mechanism of total extracts of papaya（TEP） on fatty liver fibrosis in mice. Methods Forty-eight BABL/C mice aged 4-6 weeks, half male, were evenly randomized into four groups, namely normal control group, model control group, low-dose TEP group（100 mg·kg-1） and high-dose TEP group （300 mg·kg-1）. Except that the normal control group was daily given routine diet, the other groups were given high-fat diet for modeling, and simultaneously TEP groups were given 100 and 300 mg·kg-1 respectively for 10 continuous weeks. At the fifth week, except for the normal control group, the other groups were intraperitoneally injected with porcine serum, 0.1 mL each time for three weeks. The changes in mice body weight and behavior were monitored before and after modeling, and the hepatic inflammation and fibrosis were observed under light microscope after haematoxylin-eosin （HE） staining and Masson staining. Semi-quantitative reverse transcription-polymerase chain reaction （RT-PCR） technology was applied for the detection of mRNA expression levels of protein kinase RNA-like endoplasmic reticulum kinase （PERK）, inositol-requiring kinase 1 （IRE-1）, AMP-dependent transcription factor 6 （ATF6）, the eukaryotic translation initiation factor 2 α （eIF2α ）, tissue inhibitor of metalloproteinase 1 （TIMP- 1 ）, α-smooth muscle actin （α-SMA）, and collagen type 1 （COL 1A1）. Western blot method was used for themeasurement of protein expression levels of glucose regulated protein 78 （GRP78）, tumor necrosis factor α （TNF-α）, interleukin 115 （IL-1 15 ）, and COL 1A1. Results Compared with the model group, low and high dose TEP groups showed that TEP could relieve liver damage and fibrosis, decrease the mRNA expression levels of PERK, IRE-l, ATF6, eIF2α , TIMP-1, α-SMA, and COL 1A1 （P 〈 0.05）, and lower the protein expression levels of GRP78, TNF-α, IL-1 15 , COL 1A1 （P 〈 0.05）. Conclusion TEP have significantly protective effects on fatty liver fibrosis in mice, and the mechanism may be related to counteracting the endoplasmic reticulum stress （ERS） coupling inflammation.