Recombinant human lactoferrin inhibits matrix metalloproteinase (MMP-2, MMP-3, and MMP-9) activity in a rabbit preterm delivery model

Aim: To investigate the effect of recombinant human lactoferrin (rh-LF) on the expression of matrix metalloproteinase as a marker of cervical maturation, using a rabbit preterm delivery model in which preterm labor was induced by bacteria. Methods: We used cervical tissues that had been excised in a previous study in which rabbits were randomly assigned to receive either inoculation with Escherichia coli (E. coli) or saline solution and to receive pretreatment with or without rh-LF inserted into the cervix two hours before bacterial inoculation (Condition A: saline + saline; Condition B: rh-LF + E. coli; Condition C: saline + E. coli). E. coli, saline solution, and rh-LF were inserted into the cervix using a hysteroscope and a sterile polyethylene cannula. Both cervices of the rabbit uterus, which is bicorpus-bicolli, were taken out and preserved, and expression of matrix metalloproteinases MMP-2,-3, and -9 in the cervix was evaluated using Western blot. Results: MMP-2,-3, and -9 levels in the cervix under Conditions A and B were significantly lower than that under Condition C. Conclusions: These results suggest that the prevention of preterm delivery by rh-LF in a rabbit model has been achieved through inhibition of cervical maturation promoted by matrix metalloproteinase activity.