Recombinant human lactoferrin has a potential to suppresses uterine cervical ripening in preterm delivery in animal model

Objective To investigate the effect of recombinant human lactoferrin (rhLF) on cervical ripening using a rabbit model in which preterm labor was induced by bacterial endotoxin lipopolysaccharide (LPS). Study design Timed pregnant rabbits (New Zealand White, 3–4 kg, day 14) were randomly assigned to the following treatment groups: Group A, LPS + rhLF (n = 4); Group B, LPS (n = 4); and Group C, control (n = 4). Recombinant human lactoferrin (10 μg) was administrated to pregnant rabbits in Group A and not in Group B. Lipopolysaccharide (100 μg) was given to the rabbits in both groups for 3 days (days14–16). Drugs were administered as a vaginal suppository. On day 18, the rabbits were anesthetized with intramuscular ketamine hydrochloride (20 mg/kg) and diazepam (4 mg/kg). Both cervices of the rabbit uterus, which is bicorpus-bicolli, were taken out. One cervix was placed in 10% formalin solution for a histological study with standard hematoxylin-eosin staining. The other was used for an extension test to assess the grade of ripening. Extension was measured after a 5-mm length of cervical tissue was loaded with 5.8 g. Results The histological study showed remarkably loose and edematous connective tissue in Group B cervices. Cervical tissues in Group A was not different from those in Group C. Extension lengths were 2.2 ± 0.2 mm in Group A, 7.0 ± 2.7 mm in Group B, and 1.7 ± 0.3 mm in Group C. Conclusion These results suggest that rhLF inhibits cervical maturation induced by LPS in a rabbit model and may have a potential to prevent preterm delivery caused by cervical infection and ripening.