弥散张量成像评价兔肝热缺血再灌注损伤调控肝部分切除术后肝再生的研究

Using diffusion tension imaging for evaluating the effects of warm ischemia-reperfusion injury on liver regeneration in rabbits

目的探讨弥散张量成像(DTI)评价不同程度兔肝热缺血再灌注损伤(WIRI)调控肝部分切除术后肝再生的价值。方法健康成年雄性新西兰大白兔30只,数字随机分为5组,每组6只,即对照组和10 min、20 min、30 min、40 min热缺血时间组,均行肝尾叶切除术,并于术后6 h、3 d、7 d、14 d、30 d分别进行常规磁共振及DTI扫描。30 d扫描结束后检测兔血清丙氨酸转氨酶、天冬氨酸转氨酶和乳酸脱氢酶水平,冻存肝组织血清丙二醛、髓过氧化物酶、总超氧化物歧化酶、肿瘤坏死因子α、白介素-6和增殖细胞核抗原水平,并行组织病理学检查。测量兔肝表观扩散系数(ADC)值、各项异性分数(FA)值和肝体积,并计算肝再生率(LRR)。采用重复测量方差分析比较不同随访时间各组DTI参数值、LRR的差异,采用单因素方差分析比较同一随访时间多组间DTI参数值、LRR的差异。应用Pearson或Spearman相关分析评价DTI参数值与LRR及生化指标的相关性。结果时间因素和热缺血因素的交互作用(P<0.05)及两者的单独效应(P<0.001)对ADC值的影响均具有统计学意义。不同热缺血程度、不同随访时间的FA值、LRR交互作用不显著,但时间因素的主效应显著(P<0.05)。同一热缺血组的ADC值与LRR呈显著正相关(P均<0.01);除热缺血30 min组外,各热缺血组的FA值与LRR呈负相关(P均<0.05)。术后30 d的FA值与IL-6具有较弱的相关性。结论 DTI可无创、定量评价兔肝WIRI对肝部分切除术后肝再生的影响。一定程度的WIRI(≤30 min)对兔肝部分切除术后肝再生具有促进作用,且热缺血时间越长,促进作用越明显;30 min后促进作用明显减低。

Objective To explore the value of diffusion tension imaging(DTI)in the evaluations of hepatic ischemia-reperfusion injury(WIRI)regulation of liver regeneration after partial hepatectomy.Methods Thirty healthy adult male New Zealand white rabbits were randomly divided into five groups of control and 10/20/30/40 min warm ischemia time(A0-A4)(n=6 each).Routine magnetic resonance(MR)and diffusion tensor imaging(DTI)were performed at 6 h,3 d,7 d,14 d,30 d post-keratectomy.The serum levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST)and lactate dehydrogenase(LDH)were measured at Day 30 post-keratectomy.The levels of malondialdehyde(MDA),myeloperoxidase(MPO),superoxide dismutase(SOD),tumor necrosis factor-alpha(TNF-α),interleukin-6(IL-6)and proliferating cell nuclear antigen(PCNA)in frozen liver tissues were examined and histopathological examination was performed.The values of apparent diffusion coefficient(ADC),fractional anisotropy(FA)and liver volume were measured and liver regeneration rate(LRR)was calculated.Repeated measurement analysis of variance was employed for comparing the difference of DTI and LRR in different groups at different follow-up times.One-way analysis of variance was utilized for comparing the differences of DTI and LRR between groups at the same follow-up time.Pearson or Spearman correlation analysis was employed for evaluating the correlation between DTI,LRR and biochemical parameters.Results The interaction between time and warm ischemic factor(P<0.05)and the effect of both alone(P<0.001)had statistically significant effects on ADC values.FA value and LRR interaction were not significant between time and warm ischemic factor.However,the dominant effect of time factor was significant(P<0.05).A significant positive correlation existed between ADC value and LRR in the same warm ischemia group(P<0.01).FA and LRR were negatively correlated(P<0.05),except for A3 group.FA had a weak correlation with IL-6 at Day 30 post-operation.Conclusions DTI can non-invasively and quantitatively evaluate the effect of hepatic WIRI on liver regeneration after partial hepatectomy in rabbits.A certain degree of WIRI(≤30 min)can promote liver regeneration after partial hepatectomy.The longer warm ischemia time,the more obvious promotion effect.However,the promotion effect declines significantly after 30 min.