Hepatocyte regeneration after partial liver irradiation in rats.
Liver has a strong potential for regeneration after physical, biological or chemical injury, but no data have been reported so far on liver regeneration in response to irradiation injury. The present experiment in rats was designed to clarify whether partial liver irradiation could induce and stimulate the unirradiated part of liver to regenerate. The left-half of rat liver was irradiated with a single dose of 25Gy. Liver tissues from the irradiated and unirradiated liver, and blood sample were collected at different time points after irradiation. Radiation injury was evaluated by serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, histopathologic features and trichrome stain. The hepatic regeneration was assessed by serum hepatic growth factor (HGF), mitotic index and proliferation cell nuclear antigen (PCNA) immunohistochemical stain. Expression of transforming growth factor-beta1 (TGF-beta1) by immunohistochemistry assay was also performed. Results showed that 25Gy of single-dose irradiation produced severe hepatic injury in the irradiated liver, and the unirradiated liver had been stimulated to regenerate, demonstrated by significant increases of serum HGF 30 days after irradiation, and increase of mitotic index and the number of PCNA-positive hepatocytes 60 days after irradiation. TGF-beta1 was strongly and uniformly expressed in the irradiated liver 90-day-post-irradiation, and it was also expressed slightly in unirradiated liver region. In summary, partial liver irradiation could stimulate the unirradiated liver to regenerate, and the role of TGF-beta1 in hepatic injury and proliferation needs further investigation.
Department of Radiation Oncology, Fudan University Cancer Hospital, 270 Dong An Road, Shanghai, China.
Jian Dong
JD
Zhao
Guo Liang
GL
Jiang
Wei Gang
WG
Hu
Zhi Yong
ZY
Xu
Chao Fu
CF
Wang
D000818:Animals; D022781:Hepatocytes / Q000166:cytology*; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D008940:Mitotic Index; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism / Q000528:radiation effects; D011833:Radiation Injuries, Experimental / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
D018809:Proliferating Cell Nuclear Antigen; D053773:Transforming Growth Factor beta1