Biondo-Simões Maria de Lourdes Pessole, Castro Gustavo Rodrigues Alves, Montibeller Guilherme Ramina, Sadowski José Augusto, Biondo-Simões Rachel
Department of Surgery, School of Medicine, Universidade Federal do Paraná, CEP 82030-000 Curitiba-Paraná, Brazil.
Acta Cir Bras. 2007 Mar-Apr;22 Suppl 1:52-6. doi: 10.1590/s0102-86502007000700011.
The influence of hypothyroidism in liver regeneration has been a controversial opinions.
The aim of this study is to identify the relationship between hypothyroidism and liver regeneration in rats.
Forty male Wistar rats divided into two groups of 20 specimens each. One group (C) consisted of euthyroid rats, and the other (H) of hypothyroid rats. All the animals were anesthetized with xylazine and ketamine and subjected to a longitudinal incision in the anterior cervical region. The thyroid was completely resected in group H and left intact in group C. Ten days after the first surgery, both groups of rats were weighed and submitted to partial hepatectomy, in which the left lateral and median lobes were resected and weighed. Examinations were carried out after 24 hours and, on day 7, using 3 methods: KWON et al.'s formula to identify increase in volume; mitotic figure count in five fields; and the percentage of PCNA-positive nuclei in five fields.
Using KWON's formula, the regeneration rate for Group C after 24 hours was 58.49% whereas that for Group H was 50.42% (p=0.0165). After 7 days, the regeneration rate for Group C was 93.04% and Group H 93.74% (p=0.2165). The average number of mitotic figures after 24 hours was 14 +/- 1.5 for Group C and 9.8 +/- 2.2 for Group H (p=0,00016). After 7 days the corresponding figures were 5.4 +/-1.1 and 5.1+/- 1.2 (p=0,6343). The average number of PCNA-positive nuclei after 24 hours was 13.55+/- 3.84 in Group C and 7.7 +/- 2.11 in Group H (p =0,0006)). The corresponding figures after 7 days were 3.5 +/- 2.39 for Group C and 4.11 +/-1.90 for Group H (p>0.05).
We conclude that hypothyroidism in rats causes a delay in hepatic regeneration in the first 24 hours, but that after seven days the rate of regeneration is equal to that in euthyroid rats.
甲状腺功能减退对肝脏再生的影响一直存在争议。
本研究旨在确定甲状腺功能减退与大鼠肝脏再生之间的关系。
40只雄性Wistar大鼠分为两组，每组20只。一组（C组）为甲状腺功能正常的大鼠，另一组（H组）为甲状腺功能减退的大鼠。所有动物用赛拉嗪和氯胺酮麻醉，在颈部前部做纵向切口。H组大鼠甲状腺完全切除，C组大鼠甲状腺保留完整。首次手术后10天，两组大鼠称重，然后进行部分肝切除术，切除左外侧叶和中叶并称重。在术后24小时和第7天采用3种方法进行检测：用KWON等人的公式确定体积增加；在5个视野中计数有丝分裂象；在5个视野中计数PCNA阳性细胞核的百分比。
采用KWON公式，C组术后24小时的再生率为58.49%，而H组为50.42%（p = 0.0165）。7天后，C组的再生率为93.04%，H组为93.74%（p = 0.2165）。术后24小时，C组有丝分裂象的平均数量为14±1.5，H组为9.8±2.2（p = 0.00016）。7天后相应数字分别为5.4±1.1和5.1±1.2（p = 0.6343）。术后24小时，C组PCNA阳性细胞核的平均数量为13.55±3.84，H组为7.7±2.11（p = 0.0006）。7天后，C组相应数字为3.5±2.39，H组为4.11±1.90（p>0.05）。
我们得出结论，大鼠甲状腺功能减退在最初24小时会导致肝脏再生延迟，但7天后再生率与甲状腺功能正常的大鼠相等。
