Study for the role of proteoglycans during tissue repair after acute liver injury

我们研究了蛋白多糖（PG）在D-氨基半乳糖诱导大鼠急性肝损伤后组织修复过程中的作用。抗硫酸乙酰肝素抗体和抗DELTAdi抗体免疫组化显示，在急性肝损伤早期，肝细胞内硫酸乙酰肝素PG和硫酸软骨素PG均出现一过性改变，在急性肝损伤开始后6 h，肝细胞内硫酸乙酰肝素PG一过性消失，硫酸软骨素PG呈双相染色增加;早期增加出现在6 h至3 d的血窦沿着纤维，晚期增加出现在4 d后坏死区的沿着纤维。通过北方印迹和原位杂交分析表明，硫酸软骨素-PG的晚期增加对应于核心蛋白聚糖和双糖蛋白聚糖的转录增加，这两者都是硫酸软骨素/硫酸皮肤素小PG的成员。硫酸软骨素-PG的早期增加表明对应于通过抗DELTAdi抗体鉴定的分子量为163 kDa和152 kDa的未鉴定蛋白聚糖的增加。硫酸软骨素蛋白聚糖的瞬时增加可能为细胞的增殖提供了有效的环境，因为有丝分裂需要细胞从细胞外基质中分离出来，而瞬时消失的硫酸乙酰肝素-PG通过北方印迹分析发现是纤维聚糖，膜型硫酸乙酰肝素PG之一。其他人发现纤维聚糖能够结合肝细胞生长因子，肝细胞生长因子是肝细胞的强有丝分裂原。因此，在急性肝损伤的早期阶段纤维聚糖的消失可能为HGF与c-Met（HGF的真正受体）的结合提供有效的环境，其促进组织修复期间的促有丝分裂反应。

We investigated the role of proteoglycans (PG) during tissue repair after acute liver injury induced to rats by the administration of D-galactosamine. By immunohistochemical study using anti-heparansulfate antibodies and anti DELTAdi antibodies both heparansulfate-PGs and chondroitin sulfate PGs transiently changed in the early phase of acute liver injury.Heparansulfate-PGs transiently disappeared form hepatocyte at 6h after the initiation of acute liver injury and chondroitinsufate PGs increased in staining bi-phasically ; the early increase was found along sinusoid from 6h to day 3 and the late increase was along fibers appeared in the necrotic area after day 4. Analyzes by northern blotting and in situ hybridization indicated that the late increase of chondroitinsulfate-PGs corresponded to the transcriptional increases of decorin and biglycan, both of which were the member of small chondroitinsulfate/dermatansulfate PGs. The early increase of chondroitinsulfate-PGs was indicated to correspond to the increase of unidentified proteoglycans with molecular weight of 163 kDa and 152 kDa that was identified by anti-DELTAdi antibodies. Such the transient increase of chondroitinsulfate proteoglycans may provide the environment efficient to allow the proliferation, since the mitosis requires cell detachment from the extracellular matrix.While the transiently disappearing heparansulfate-PGs was found by northern blot analysis to be fibroglycan, one of membrane type heparansulfate PGs. It was found by others that fibroglycan was capable to bind hepatocyte growth factor, which was a strong mitogen of hepatocytes. Thus, the disappearance of fibroglycan at an early phase of acute liver injury may provide an environment efficient for the binding of HGF to c-Met, true receptor for HGF,which promote the mitogenic response during tissue repair.