Fetal monkey surfactants after intra-amniotic or maternal administration of betamethasone and thyroid hormone.
OBJECTIVE
To compare direct intra-amniotic injection of betamethasone and thyroxine (T4) with maternal treatment and controls for accelerating pulmonary surfactant production.


METHODS
Twelve pregnant monkeys (Macaca mulatta) on gestational day 125 (term 165 +/- 10 days) had surfactant protein A and B concentrations measured in amniotic fluid. In four controls, normal saline was injected into the amniotic fluid; four others (intra-amniotic) received intra-amniotic betamethasone (1 mg) and T4 (60 microg); and in four others (maternal), the dam was given betamethasone (12 mg) intramuscularly, repeated in 24 hours, plus TRH (400 microg) intravenously, repeated every 6 hours for 24 hours. Seventy-two hours after the initial amniocentesis, a hysterotomy was performed and fetal tissue and amniotic fluid harvested for determination of surfactant protein A and B concentrations and immunohistochemical staining for surfactant protein A.


RESULTS
Amniotic fluid surfactant protein A was higher with intra-amniotic injection than with maternal treatment (P <.04) or controls (P =.07). Amniotic fluid surfactant protein B was higher in the intra-amniotic group than in controls (P =.06). Immunohistochemical staining for surfactant protein A in the lung tissue was increased in the intra-amniotic group compared with controls (0.145 +/- 0.01 versus 0.097 +/- 0.001, percent positive staining for surfactant protein A cells per lung tissue cells; P <.03). Birth weight was greater in the intra-amniotic group compared with the maternal group (P <.03) although not different from the controls. Finally, gut motility and the presence of formed meconium were increased in the intra-amniotic group compared with the other groups (P <.05).


CONCLUSIONS
Intra-amniotic injection of betamethasone and T4 enhanced lung (and possibly intestinal) maturation of the preterm rhesus fetal monkey compared with maternal injections.
Gilbert
W M
WM
Department of Obstetrics and Gynecology, University of California, Davis, Sacramento, California 95817, USA. wmgilbert@ucdavis.edu
Eby-Wilkens
E
E
Plopper
C
C
Whitsett
J A
JA
Tarantal
A F
AF
D000653:Amniotic Fluid / Q000737:chemistry*; D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis*; D007150:Immunohistochemistry; D007267:Injections; D008253:Macaca mulatta; D011247:Pregnancy; D011498:Protein Precursors / Q000096:biosynthesis*; D011510:Proteolipids / Q000096:biosynthesis*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000096:biosynthesis*; D013974:Thyroxine / Q000008:administration & dosage / Q000494:pharmacology*
D006023:Glycoproteins; D011498:Protein Precursors; D011510:Proteolipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C105511:surfactant protein B propeptide; D001623:Betamethasone; D013974:Thyroxine