基于压痕松弛实验的黏弹性参数评价大鼠肝纤维化的实验研究

目的探讨基于压痕松弛实验的黏弹性参数评价肝纤维化的可行性，以期为弹性成像诊断肝纤维化提供有价值的参数和方法。 方法选取雄性SD大鼠50只，平均体质量（180±20）g，将其分为2组，肝纤维化组（40只）和对照组（10只）。最终纳入43只，其中肝纤维化组36只，对照组7只。实验组大鼠采用四氯化碳-橄榄油溶液建立肝纤维化模型，对照组大鼠采用单纯橄榄油溶液灌胃。分离大鼠肝脏后进行压痕松弛实验，测算肝脏黏弹性参数。对离体肝脏病理标本进行肝组织纤维化分期（S1~S4期）。对不同肝纤维化分期的各组大鼠黏弹性参数进行比较，并进行黏弹性参数与大鼠肝纤维化程度的相关性分析。 结果对照组与肝纤维化S1~S4期各组的黏弹性参数应力下降开始时的变化程度（g₁）、应力降低到平衡时的变化程度（g₂）、黏弹性材料的总松弛程度（g₁＋g₂）、应力下降开始时间（τ₁）、应力降低到平衡时的时间（τ₂）进行比较，τ₁、τ₂、g₁组间差异有统计学意义（F=23.598、2.836、2.506，P均<0.05），进一步两两比较，黏弹性参数τ₁在正常肝脏组与S1、S2、S3、S4期肝纤维化组之间的差异均有统计学意义（t=2.367、1.689、2.887、3.195，P均<0.05）；黏弹性参数τ₂在S1期和S3期肝纤维化组之间差异有统计学意义（t=2.048，P<0.05）；黏弹性参数g₁在S2期和S3期肝纤维化组之间差异有统计学意义（t=3.211，P<0.05）。Spearman相关性分析显示，黏弹性参数g₁、g₁＋g₂与肝纤维化程度呈正相关（r=0.513、0.439，P均<0.001），τ₁与肝纤维化程度呈负相关（r=-0.509，P<0.001）。 结论黏弹性参数与肝纤维化分期具有相关性，将黏弹性参数应用于大鼠肝脏纤维化分期的评估具有可行性，这也为黏弹性参数运用于剪切波弹性成像评价肝纤维化提供了可靠的实验论据。

Indentation relaxation test based viscoelastic parameters for evaluation of liver fibrosis in rats

ObjectiveTo explore the feasibility of viscoelastic parameters based on the indentation relaxation test in evaluating liver fibrosis, so as to provide valuable parameters and methods for elastography in diagnosing liver fibrosis. MethodsFifty male SD rats with an average body mass of (180±20) g were selected and divided into two groups: a liver fibrosis group (n=40) and a control group (n=10). Finally, 43 SD rats were included, including 36 in the hepatic fibrosis group and 7 in the control group. Liver fibrosis was induced in rats with carbon tetrachloride, while the control group was fed olive oil solution alone. The indentation relaxation test was performed to determine the viscoelastic parameters of the liver after liver isolation. Liver fibrosis staging (stages S1~S4) was performed on isolated liver pathological specimens. The viscoelastic parameters of different liver fibrosis stages in rats were compared and the correlation between viscoelastic parameters and the degree of liver fibrosis in rats was analyzed. ResultsViscoelastic parameters τ₁, τ₂, and g₁ were statistically significant different between the groups (F=23.598, 2.836, and 2.506, respectively, all P<0.05). In further pairwise comparisons, τ₁ was statistically different between the control group and group S1, S2, S3, or S4 (t=2.367, 1.689, 2.887, and 3.195, respectively, all P<0.05). τ₂ was statistically different between groups S1 and S3 (t=2.048, P<0.05), and g₁ was statistically different between groups S2 and S3 (t=3.211, P<0.05). Spearman correlation analysis showed that viscoelastic parameters g₁ and g₁+ g₂ were positively correlated with the degree of liver fibrosis (r=0.513 and 0.439, respectively, both P<0.001), while τ₁ was negatively correlated with the degree of liver fibrosis (r=-0.509, P<0.001). ConclusionViscoelastic parameters correlate with liver fibrosis stages, so it is feasible to use viscoelastic parameters to evaluate liver fibrosis stage in rats, which provides reliable experimental evidence for the application of viscoelastic parameters in shear wave elastography to evaluate liver fibrosis.