Enhanced secretory group II PLA2 activity in the tears of chronic blepharitis patients.
OBJECTIVE
Phospholipase A2 (PLA2) hydrolyzes phospholipids, one of the important constituents of human meibomian gland secretions. This study was performed to investigate PLA2 type and activity in the tears of chronic blepharitis patients compared to those of normal persons.


METHODS
Tear samples of 36 patients and 10 normal persons were collected in non-heparinized microcapillary tubes. PLA2 activity in the tears was measured by Dole's method, and the results of the blepharitis patients were compared to those of the normal persons. The characterization of PLA2 was performed by the head group preference test and the dithiothreitol (DTT) sensitivity test. The classification of PLA2 type was done using Western blot analysis with anti-human secretory PLA2 antibody.


RESULTS
No statistically significant differences were found among the six categories of chronic blepharitis. However, the mean PLA2 activity in the tears of the chronic blepharitis patients was about two times higher than that of the normal controls with statistical significance (P < 0.05). The PLA2 substrate specificity test revealed group II PLA2 activity. Furthermore, the group II PLA2 was identified as a 14 kDa band in Western blot analysis using an antibody raised against human secretory group II PLA2.


CONCLUSIONS
Secretory group II PLA2 activity was significantly enhanced in the tears of the chronic blepharitis patients compared with that of the normal controls. It is suggested that this increased enzymatic activity may decrease the tear film stability through increased hydrolysis of phospholipids.
Song
C H
CH
Department of Ophthalmology, Chung-Ang University Hospital, Seoul, Korea.
Choi
J S
JS
Kim
D K
DK
Kim
J C
JC
D000328:Adult; D001762:Blepharitis / Q000201:enzymology*; D015153:Blotting, Western; D002908:Chronic Disease; D005260:Female; D054501:Group II Phospholipases A2; D006801:Humans; D008297:Male; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D013666:Tears / Q000201:enzymology*
D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2