Effect of laser light on the hepatic regeneration of hypothermically preserved remnant livers after partial 70% hepatectomy

Abstract

After partial hepatectomy (PH), the remnant liver (RL) shows a regenerative response, always keeping a percent relation with the host. There are no precise data in the literature about RL regeneration during hypothermal preservation. The objective of the present study is to analyze RL regeneration after PH under conditions of hypothermal preservation with and without a laser light stimulus. Method: According to the sample size calculation of Kelley and Maxwell, 56 Wistar rats will be divided into four major groups of 14 animals each: NPWL, non-perfused whole liver (control); PWL, perfused whole liver; PHS, 70% PH in situ, and PPH, 70% perfused PH. Laser light at 660 nm wavelength at 30 mw, using the dose of 22.5 J/cm2, will be applied to half the animals in each group.All animals will be submitted to general anesthesia. The time for the analysis of tissue parameters will be 12 and 24 hours. The liver will be perfused with 250 ml of Celsior solution with a catheter connected to a 1.30 cm-high liquid column. Twelve and 24 hours after the surgical act, hepatic tissue samples will be submitted to analysis of the protein expression of Ki67, to analysis of the expression profile of the miR-21 and miR-16 microRNAs by real time PCR, and to analysis of mitochondrial function by the polarographic method. Data will be analyzed statistically by the Mann-Whitney test with the level of significance set at 5%.