A BASIC STUDY ON INDUCTION OF APOPTOSIS IN COWS WITH FATTY LIVER

奶牛脂肪肝被认为是围产期疾病的主要发病机制。这种损伤是由分娩前后能量失衡引起的。阐明其发病机制是控制围产期疾病不可缺少的环节。本研究采用文献报道的4天禁食模型(实验1)，研究了细胞凋亡在奶牛脂肪肝发生发展过程中的作用。此外，我们还评估了过渡期对奶牛肝脏细胞凋亡的诱导作用(实验2)。实验11.禁食4天后，大鼠肝脏甘油三酯(TG)含量升高，并出现脂肪肝。2.彗星试验观察到脂肪肝形成过程中肝细胞核碎裂增多。3.免疫组织化学分析，在脂肪肝形成过程中可见与细胞凋亡相关的抗体阳性细胞。4.超微结构分析证实有凋亡小体。实验21.第3天和第21天肝脏TG含量较造模前增加一倍以上。2.肝细胞核碎裂在第3天至第21天增加。并用上述免疫组织化学方法观察阳性细胞。3.彗星试验显示肝脏TG含量与尾距呈显著正相关(r=0.68)。在实验性脂肪肝和正常产犊后，均证实了脂肪肝对细胞凋亡的诱导作用。这一现象被认为是对活体的控制。我们正计划研究脂肪肝中细胞凋亡的触发因素。

The fatty liver in dairy cattle is known as a primary pathogenesis of periparturient diseases. This lesion is induced by energy imbalance around parturition. The elucidation of the pathogenesis is indispensable to control periparturient diseases. In this study, apoptosis in the development of fatty liver of cows was evaluated by use of 4-days-fasting model reported previously (Exp.1). Further we assessed the induction of apoptosis in the livers of cows through transition period (Exp.2). Obtained data are as the followings.Exp.11.By fasting for 4 days, liver triglyceride (TG) content was increased and fatty liver was admitted.2.The increase of nuclear fragmentation in hepatic cells was observed in the development of fatty liver by use of comet assay.3.In immunohistological analysis, the positive cells to antibodies related to apoptosis induction were observe in the development of fatty liver.4.In ultramorphological analysis, apoptotic body was verified.Exp.21.The liver TG contents at day 3 and 21 were more than twice as much as that before calving.2.The nuclear fragmentation in hepatic cells was increased from day 3 to day 21. Further, the positive cells were observed using above-mentioned immunohistological analysis. Apoptotic body was also verified.3.The relationship between liver TG content and tail moment in comet assay was significantly positive (r=0.68).The induction of apoptosis in cows with fatty liver was verified in the experimental fatty liver and after usual calving. The phenomenon was considered the control of a living body. We are planning to study about the triggers of apoptosis in the fatty liver.