Activation of mucosal phospholipase D in a rat model of colitis.
OBJECTIVE
Phospholipase D (PLD) hydrolyzes phosphatidylcholine and produces lipid second messengers. Although cellular PLD has recently been recognized as an important signal-transmitting enzyme, the role of PLD in pathophysiologic conditions is largely unknown. In particular, the regulation of PLD in intestinal inflammation has not been previously investigated. The aim of the present study was to elucidate the role of PLD in experimental colitis.


METHODS
Rats were intracolonically administered acetic acid and assessed for mucosal damage, mucosal PLD activity, mucosal myeloperoxidase activity, mucosal chemiluminescence and luminal concentration of leukotriene B4. Acetic acid treatment induced acute mucosal injury that was maximal at 24 h after treatment.


RESULTS
Mucosal PLD activity was significantly elevated and correlated with mucosal damage. Chemiluminescence in colitic mucosa was inhibited by the addition of ethanol which suppresses the formation of phosphatidic acid catalyzed by PLD.


CONCLUSIONS
These results suggest that PLD is activated in experimental colitis in rats and that PLD may play a role in mucosal damage induced by reactive oxygen metabolites.
Sakamoto
T
T
First Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan.
Okamura
S
S
Saruya
S Y
SY
Yamashita
S
S
Mori
M
M
D000085:Acetates / Q000008:administration & dosage; D000208:Acute Disease; D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology; D003092:Colitis / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D003106:Colon / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D003627:Data Interpretation, Statistical; D004195:Disease Models, Animal; D004789:Enzyme Activation; D000431:Ethanol / Q000494:pharmacology; D005260:Female; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D007975:Leukotriene B4 / Q000378:metabolism; D008163:Luminescent Measurements; D009195:Peroxidase / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000085:Acetates; D002492:Central Nervous System Depressants; D010743:Phospholipids; D007975:Leukotriene B4; D000431:Ethanol; D009195:Peroxidase; D010739:Phospholipase D