[Protein tyrosine kinase activation in the repair of rat gastric mucosa after damage].
OBJECTIVE
To investigate the possible role of protein tyrosine kinase (PTK) and its effect on nuclear protein phosphorylation and activating protein 1 (AP-1) activity in the rat gastric epithelial restitution.


METHODS
Rat gastric mucosae were damaged with 20 mmol/L Deoxysodium cholate (DOC). Mucosal scrapings from the oxyntic gland area were obtained 3 hours after damage. The cellular membrane and nuclear fractions were dissociated from the extraction of the mucosal scrapings to assay the activity of PTK and AP-1, and the phosphorylation of nuclear protein. Different blockers, including Tyrphostin-51 for PTK and PD098059 for mitogen-activated protein kinase kinase (MAPKK), were used to study the signaling control for a better understanding of the mechanisms of gastric reepithelium.


RESULTS
20 mmol/L DOC caused moderate damage in rat gastric mucosae. PTK activity 3 hours after damage was 1 time that of the primary level, while nuclear protein phosphorylation level was increased about 4 folds. Tyrphostin-51 and PD098059 inhibited such effects by 85.3% and 61.6%, respectively. AP-1 activity was also greatly elevated after gastric mucosal damage and the effect was attenuated by both Tyrpsotin-51 and PD098059.


CONCLUSIONS
PTK activation improves the rat gastric mucosal repair ability in the early phase after damage through the promotion of nuclear protein phospharylation and the increase in AP-1 activity. The effect of PTK is greatly magnified when the signals fly into the cellular nuclea, mainly through MAPK pathway.
Zeng
J
J
PLA Institute of Digestive Diseases, First Military Medical University, Guangzhou 510515.
Zheng
Q
Q
Zhang
W
W
D000818:Animals; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D005753:Gastric Mucosa / Q000201:enzymology / Q000473:pathology*; D008297:Male; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051818:Replication Protein C
D004268:DNA-Binding Proteins; D011505:Protein-Tyrosine Kinases; D051818:Replication Protein C