Inositol and glucocorticoid in the development of lung stability in male and female rabbit fetuses

Abstract

Inasmuch as inositol affects the development of lung surfactant, and exogenous glucocorticoids acceler­ate fetal lung maturation, a possible interaction of the two substances on alveolar stability of preterm rabbit fetuses of 28 days gestation was investigated. On days 26 and 27 of gestation inositol or glucose were added to the diet of does treated with betamethasone (0.2 mg/kg intramuscu­larly on days 26 and 27). Inositol increased lung-thorax compliance of paralyzed fetuses at all insufflation pres­sures studied (from 16 to 22.5 and 30 cm H20 and back to 22.5, and 16 cm H20). At a ventilation pressure of 30 cm H2O, lung-thorax compliance of fetuses treated with ino­sitol plus betamethasone was more than doubled as com­pared with controls (1.2 ± 0.6 versus 0.5 ± 0.2 ml/kg X cm H2O; p < 0.001). Inositol alone had no detectable effect on compliance, whereas betamethasone tended to increase compliance (p = 0.05). According to variance analysis, the effect of inositol was statistically significant only among the males. Inositol prevented the glucocorticoid-induced decrease in lung protein and, to a lesser extent, the decrease in DNA. Inositol did not further increase the lavageable surfactant pool of the glucocorticoid-treated, ventilated fetuses, although the area occupied by lamellar bodies within type II cells was increased after inositol plus beta­methasone. According to the present study, inositol modi­fies the physiologic and biochemical response of the im­mature fetal lung to a pharmacologic dose of exogenous glucocorticoid. © 1988 International Pediatrics Research Foundation, Inc.