Indomethacin promotes germinal matrix microvessel maturation in the newborn beagle pup.
OBJECTIVE
Although indomethacin has been demonstrated to prevent germinal matrix and intraventricular hemorrhage in clinical and animal studies, the mechanism of action of this agent to prevent hemorrhage remains unclear. Previous studies have demonstrated both that the microvessels in the germinal matrix of newborn beagle pups undergo basement membrane maturation during the first 4 postnatal days and that indomethacin may promote laminin deposition in tumor cell culture systems.


METHODS
We employed the newborn beagle pup model to test the hypothesis that indomethacin may stimulate laminin deposition in germinal matrix microvessels. Newborn pups were randomized to receive either 0.1 mg/kg/dose i.p. indomethacin or an equal volume of saline diluent. Pups received doses of study medication once a day for 1, 2, or 3 days and were studied on postnatal days 1, 2, 3, or 4. Pups were anesthetized and systemically perfused with buffered formalin; the brains were removed and prepared for immunohistochemical study.


RESULTS
Sections stained with Bandeiraea lectin demonstrated that there was no difference in germinal matrix vessel density among the postnatal ages studied; similarly, there were no differences in vessel density between saline- and indomethacin-treated animals at any postnatal age. Quantification of germinal matrix stained intensity by confocal microscopy demonstrated significant increases in indomethacin-treated pups for both laminin staining at postnatal days 2 (p = 0.05) and 3 (p = 0.0009) and type V collagen staining at postnatal day 2 (p = 0.011). Although staining for beta 1 integrins increased across postnatal ages, there were no differences between saline- and indomethacin-treated animals.


CONCLUSIONS
These data suggest that indomethacin may stimulate basement membrane deposition in the germinal matrix microvessels of newborn beagle pups to prevent germinal matrix and/or intraventricular hemorrhage.
Ment
L R
LR
Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510.
Stewart
W B
WB
Ardito
T A
TA
Huang
E
E
Madri
J A
JA
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001921:Brain / Q000098:blood supply*; D002543:Cerebral Hemorrhage / Q000378:metabolism*; D002552:Cerebral Ventricles / Q000098:blood supply* / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D004285:Dogs; D005855:Germ Layers / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism; D008833:Microcirculation
D007797:Laminin; D003094:Collagen; D007213:Indomethacin