Department of Cytophysiology, Chair of Histology and Embryology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, 40-752 Katowice, Poland.
Students Scientific Society, Chair of Histology and Embryology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, 40-752 Katowice, Poland.
Front Biosci (Landmark Ed). 2023 May 9;28(5):87. doi: 10.31083/j.fbl2805087.
In humans, chronic liver disease (CLD) is a serious clinical condition with many life-threatening complications. Currently, there is no therapy to stop or slow down the progression of liver fibrosis. Experimental mouse models of CLD, induced by repeated intraperitoneal injections of carbon tetrachloride (CCL4) and D-galactosamine (D-GalN), can be used to evaluate therapies that cannot be performed in humans. A major drawback of these animal models is the different dynamics of liver fibrosis progression depending on the animal strain, administered hepatotoxin, its dose, duration of intoxication, and frequency of injections. The aim of this study was to describe and compare the dynamics of progression of pathological changes in the BALB/c mouse and Sprague Dawley rat models of CLD induced by CCl4 and D-GalN. We defined the onset and duration of these changes and suggested the optimal time for therapeutic intervention in the analyzed CLD models.
CLD was induced by repeated intraperitoneal injection of CCl4 in mice (12.5 μL/100 g bw every 5 days) and rats (25-100 μL/100 g bw twice a week) and D-GalN in mice (75 mg/100 g bw twice a week) and rats (25 mg/100 g bw twice a week). Blood and liver samples were collected at weeks 2, 4, 6, 8, 10, and 12 of intoxication. Liver injury and its progression were assessed by using complete blood count and liver function blood tests as well as by analyzing histopathological changes, including fibrosis, proliferation activity, apoptosis, stellate cell activation, and gene expression.
In mice and rats treated with CCl4, early fibrosis was observed in most pericentral areas from week 2 to 4 of intoxication. Established fibrosis developed in both rats and mice at week 6 of intoxication. Incomplete cirrhosis, defined as the presence of occasional cirrhotic nodules, was observed in rats at week 12 of intoxication. The dynamics of liver fibrosis in CCl4-treated animals were greater than in the D-GalN groups. In D-GalN-intoxicated rats and mice, the first signs of liver fibrosis were observed at weeks 4 and 10 of intoxication, respectively. The rats developed early fibrosis after 8 weeks of D-GalN intoxication. The progression of collagen deposition was accompanied by histological changes and alteration of certain genes and blood liver parameters.
The dynamics of liver fibrosis in CCl4 treated rodents is greater than in the D-GalN treated ones. In the CCl4 models, two appropriate times for therapeutic intervention are indicated, which to varying degrees reflect the real clinical situation and may potentially differ in the obtained results: early intervention before week 4 of intoxication (early fibrosis) and late intervention after week 8 of intoxication (when signs of established fibrosis are present). Rodent models of D-GalN-induced fibrosis are not recommended due to the long incubation period and weak toxic effect.
在人类中，慢性肝病（CLD）是一种严重的临床病症，有许多危及生命的并发症。目前，尚无阻止或减缓肝纤维化进展的疗法。使用反复腹腔内注射四氯化碳（CCl4）和 D-半乳糖胺（D-GalN）诱导的 CLD 实验小鼠模型可用于评估无法在人类中进行的疗法。这些动物模型的一个主要缺点是肝纤维化进展的动力学因动物品系、给予的肝毒素、其剂量、中毒持续时间和注射频率而异。本研究的目的是描述和比较 CCl4 和 D-GalN 诱导的 BALB/c 小鼠和 Sprague Dawley 大鼠 CLD 模型中病理变化进展的动力学。我们定义了这些变化的开始和持续时间，并提出了在分析的 CLD 模型中进行治疗干预的最佳时间。
通过反复腹腔内注射 CCl4（小鼠：12.5 μL/100 g bw，每 5 天一次；大鼠：25-100 μL/100 g bw，每周两次）和 D-GalN（小鼠：75 mg/100 g bw，每周两次；大鼠：25 mg/100 g bw，每周两次）诱导 CLD。在中毒的第 2、4、6、8、10 和 12 周收集血液和肝脏样本。通过全血细胞计数和肝功能血液检查以及分析组织病理学变化，包括纤维化、增殖活性、细胞凋亡、星状细胞激活和基因表达，评估肝损伤及其进展。
在接受 CCl4 治疗的小鼠和大鼠中，从中毒的第 2 周到第 4 周，大多数周边区即可观察到早期纤维化。在中毒的第 6 周，大鼠和小鼠均出现了已建立的纤维化。在中毒的第 12 周，大鼠出现了不完整的肝硬化，定义为偶尔存在肝硬化结节。CCl4 处理动物的肝纤维化动力学大于 D-GalN 组。在 D-GalN 处理的大鼠和小鼠中，分别在中毒的第 4 周和第 10 周观察到肝纤维化的最初迹象。在 D-GalN 中毒 8 周后，大鼠出现早期纤维化。胶原沉积的进展伴随着组织学变化和某些基因和血液肝脏参数的改变。
CCl4 处理的啮齿动物的肝纤维化动力学大于 D-GalN 处理的动物。在 CCl4 模型中，有两个适当的治疗干预时间，这两个时间在不同程度上反映了真实的临床情况，并且可能在获得的结果中有所不同：在中毒的第 4 周之前的早期干预（早期纤维化）和中毒的第 8 周之后的晚期干预（当出现已建立的纤维化迹象时）。由于潜伏期长且毒性作用弱，不建议使用 D-GalN 诱导的纤维化啮齿动物模型。
