title: Low-power laser irradiation fails to improve liver regeneration in elderly rats at 48 h after 70 % resection.
abstract: The liver regeneration is an important clinical issue after major hepatectomies. Unfortunately, many organs (including the liver) exhibit age-related impairments regarding their regenerative capacity. Recent studies found that low-power laser irradiation (LPLI) has a stimulatory effect on the liver regeneration process. However, its effects in elderly remain unknown. Thus, this study aimed to investigate the main molecular mechanisms involved in liver regeneration of partially hepatectomized elderly rats exposed to LPLI. The effects of 15 min of LPLI (wavelength of 632.8 nm; fluence of 0.97 J/cm(2); total energy delivered of 3.6 J) were evaluated in hepatectomized elderly Wistar male rats. Afterwards, through immunoblotting approaches, the protein expression and phosphorylation levels of hepatocyte growth factor (HGF), Met, Akt and Erk 1/2 signaling pathways as well as the proliferating cell nuclear antigen (PCNA) were investigated. It was observed that LPLI was not able to improve liver regeneration in elderly rats as evidenced by the lack of improvement of HGF and PCNA protein expression or phosphorylation levels of Met, Akt and Erk 1/2 in the remnant livers. In sum, this study demonstrated that the main molecular pathway, i.e. HGF/Met → Akt and Erk 1/2 → PCNA, involved in the hepatic regeneration process was not improved by LPLI in elderly hepatectomized rats, which in turn rules out LPLI as an adjuvant therapy, as observed in this protocol of liver regeneration evaluation (i.e. at 48 h after 70 % resection), in elderly.
authors.affiliation: Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, 13081-970, Brazil, tigaraujo@hotmail.com.
authors.forename: Tiago G
authors.initials: TG
authors.lastname: Araújo
authors.forename: Alexandre G
authors.initials: AG
authors.lastname: Oliveira
authors.forename: Natália
authors.initials: N
authors.lastname: Tobar
authors.forename: Luciana R
authors.initials: LR
authors.lastname: Moreira
authors.forename: Edmyr R
authors.initials: ER
authors.lastname: Reis
authors.forename: Ester M D
authors.initials: EM
authors.lastname: Nicola
authors.forename: Gracinda
authors.initials: G
authors.lastname: de L Jorge
authors.forename: Rodolfo
authors.initials: R
authors.lastname: dos R Tártaro
authors.forename: Ilka F S F
authors.initials: IF
authors.lastname: Boin
authors.forename: Mário J Abdalla
authors.initials: MJ
authors.lastname: Saad
authors.forename: Antonio R Franchi
authors.initials: AR
authors.lastname: Teixeira
mesh_terms: D000375:Aging; D000818:Animals; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D008099:Liver / Q000378:metabolism / Q000503:physiopathology / Q000528:radiation effects; D008115:Liver Regeneration / Q000528:radiation effects*; D028022:Low-Level Light Therapy; D020935:MAP Kinase Signaling System; D008297:Male; D018809:Proliferating Cell Nuclear Antigen; D051381:Rats; D017208:Rats, Wistar
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D017228:Hepatocyte Growth Factor