Acetylsalicylic acid (Aspirin®) and liver regeneration: experimental study in rats

ABSTRACT Objective: to evaluate the influence of acetylsalicylic acid (ASA) on cell proliferation after partial hepatectomy in rats. Methods: 40 male Wistar rats were separated into four groups of ten rats each. Groups 1 and 2 (controls): undergoing 30% partial hepatectomy and, after one day (group 1) and seven days (group 2), to euthanasia; daily administration of 0.9% saline solution (1mL per 200g of body weight). Groups 3 and 4 (experimental): undergoing 30% partial hepatectomy and, after one day (group 3) and seven days (group 4), to euthanasia; daily administration of ASA (40mg/mL, 1mL per 200g of body weight). The absolute number of cells stained with PCNA was counted in photomicrographs, in five fields, and it was calculated the mean of positive cells per animal and per group. Results: the final mean of PCNA+ cells per group was: in group 1, 17.57 ± 6.77; in group 2, 19.31 ± 5.30; in group 3, 27.46 ± 11.55; and, in group 4, 12.40 ± 5.23. There was no significant difference at the two evaluation times in the control group (p=0.491), but there was in the experimental group (p=0.020), with a lower number of PCNA+ cells on the seventh day. The comparison between the two groups, on the first day, showed more PCNA+ cells in the livers of the animals that received ASA (p=0.047), and on the seventh day the number was lower in the experimental group (p=0.007). Conclusion: ASA induced greater hepatocyte proliferation. RESUMO Objetivo: avaliar a influência do ácido acetilsalicílico (AAS) na proliferação celular após hepatectomia parcial em ratos. Métodos: 40 ratos Wistar machos foram separados em quatro grupos com dez ratos cada. Grupos 1 e 2 (controles): submetidos à hepatectomia parcial de 30% e, após um (grupo 1) e sete dias (grupo 2), à eutanásia; administração diária de solução fisiológica 0,9% (1mL por 200g de peso). Grupos 3 e 4 (experimentos): submetidos à hepatectomia parcial de 30% e, após um (grupo 3) e sete dias (grupo 4), à eutanásia; administração diária de AAS (40mg/mL, 1mL por 200g de peso). Realizou-se a contagem do número absoluto de células coradas com PCNA em fotomicrografias, em cinco campos e cálculo da média de células positivas por animal e por grupo. Resultados: A média final de células PCNA+ por grupo foi: no grupo 1, de 17,57 ± 6,77; no grupo 2 de 19,31 ± 5,30; no grupo 3, de 27,46 ± 11,55; e, no grupo 4, de 12,40 ± 5,23. Não houve diferença significante nos dois tempos de avaliação no grupo controle (p=0,491), mas houve no grupo exp