Critical period of bilirubin-induced cerebellar hypoplasia in a new Sprague-Dawley strain of jaundiced Gunn rats.
Homozygous (j/j) and heterozygous (j/+) newborn Gunn rats of the Sprague-Dawley strain were photoirradiated for 24 h at scheduled postnatal days and the effects of irradiation on the cerebellar development were examined at 30 days of life. Improvement of the survival rate was the most notable effect of photoirradiation. A single 24-h dose of photoirradiation during a period of postnatal days 4-11 effectively prevented hypoplasia in the j/j rat cerebellum. No prevention by light was observed at days 3 and 12. It was found that the most effective day of irradiation on the cerebellar development of j/j rats was centered on postnatal day 7. When plasma bilirubin was assessed during the period of postnatal days 7-10, a distinct diminution of the concentration was observed, restricted to only the period of the light treatment. Although there were some differences in the effective day as well as in the degree of efficacy of phototherapy among cerebellar lobules or sublobules, day 7 was the most critical for cerebellar hypoplasia due to bilirubin.
Keino
H
H
Department of Perinatology, Aichi Prefecture Colony, Japan.
Kashiwamata
S
S
D000818:Animals; D001663:Bilirubin / Q000097:blood* / Q000528:radiation effects; D002526:Cerebellar Diseases / Q000209:etiology* / Q000473:pathology; D002531:Cerebellum / Q000528:radiation effects; D006801:Humans; D007231:Infant, Newborn; D007567:Jaundice, Neonatal / Q000150:complications / Q000628:therapy*; D010789:Phototherapy; D011689:Purkinje Cells / Q000528:radiation effects; D051381:Rats; D011911:Rats, Gunn; D011919:Rats, Inbred Strains; D013997:Time Factors
D001663:Bilirubin