Rapid response of hepatocyte growth factor in pulmonary ischemia in a rat model.

Hepatocyte growth factor (HGF) is a multifunctional factor implicated in tissue regeneration, wound healing, and angiogenesis. HGF was initially thought to be liver-specific, but it has become clear that HGF acts on alveolar type II cells and bronchial epithelial cells. This study was conducted to determine the role of HGF in pulmonary ischemia in a rat model. The first increase of the plasma HGF level was noted 30 min after pulmonary ischemia, and reached a peak at 12 h. Real-time reverse transcription polymerase chain reaction (Real-time RT-PCR) revealed that the HGF messenger RNA (mRNA) expression in the injured left lung was markedly increased at 1, 6, and 12 h after pulmonary ischemia (P < 0.05). The interleukin-1beta (IL-1beta) mRNA expression, one of the inflammatory cytokines which induces HGF expression, was markedly increased at 1 h in the injured left lung (P = 0.0007). Therefore, we considered that HGF might be mainly induced by paracrine mechanisms in pulmonary ischemia. In conclusion, we have shown that the expression of HGF was induced in pulmonary ischemia, and may be a useful biological marker for the early diagnosis.