Expression of transforming growth factor-alpha and epidermal growth factor receptor mRNA in the gastric mucosa of portal hypertensive rats.
OBJECTIVE
TGF-alpha (transforming growth factor-alpha) is a polypeptide that binds to the epidermal growth factor receptor and may play a role in gastric epithelial proliferation as well as the repair of injured gastric mucosa. Our previous studies have demonstrated that gastric mucosa TGF-alpha and epidermal growth factor receptor were significantly increased in rats with portal hypertension using the immunohistochemical analysis. Thus, the present study aimed to confirm the effect of portal hypertension on the expression of gastric TGF-alpha and epidermal growth factor receptor mRNA and to localize gastric TGF-alpha and epidermal growth factor receptor mRNA production sites in rats.


METHODS
Portal hypertension was induced experimentally by partial ligation of the portal vein in 12 male Wistar rats (PVL group), and in another group of 12 rats (control) that received sham operations. The severity of gastric mucosal lesions was evaluated macroscopically by a gross ulcer index. We simultaneously detected the expression of TGF-alpha and epidermal growth factor receptor mRNA in the gastric tissues of control and portal hypertensive rats by the reverse transcription-polymerase chain reaction and in situ hybridization.


RESULTS
The portal pressure and gross gastric mucosal damage differed significantly between the PVL group and the control group (p < 0.001 and p = 0.001, respectively). The expression of TGF-alpha and epidermal growth factor receptor mRNA was significantly increased in portal hypertensive rats compared to the control using the reverse transcription-polymerase chain reaction (both p < 0.01). Additionally, in situ hybridization showed the TGF-alpha and epidermal growth factor receptor mRNA were more intense in the PVL group compared to the control. TGF-alpha mRNA was located primarily in the parietal cells of the gastric fundic glands and in the surface epithelial cells, whereas epidermal growth factor receptor mRNA was mainly in the mucous neck cells of the proliferative zone and some parietal cells.


CONCLUSIONS
From these findings, we suggest that the enhanced TGF-alpha and epidermal growth factor receptor production may play an important role in the gastric mucosal regeneration of portal hypertensive rats through the increased mRNA expression.
Department of Surgery, Kaohsiung Medical University Hospital, No. 100, Shih Chuan 1st Road, Kaohsiung 807, Taiwan. cy614112@ms14.hinet.net
Jan-Sing
JS
Hsieh
Jaw-Yuan
JY
Wang
Shiu-Ru
SR
Lin
Tsuty-Jiuan
TJ
Hsieh
Tsung-Jen
TJ
Huang
D000818:Animals; D066246:ErbB Receptors / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D006975:Hypertension, Portal / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D066246:ErbB Receptors