Strength and histology of a nanofiber scaffold in rats

Full-thickness soft tissue defects from congenital absence or traumatic loss are difficult to surgically manage. Healing requires cell migration, organization of an extracellular matrix, inflammation, and wound coverage. PLCL (70:30 lactide:caprolactone, Purac), poly(propylene glycol) nanofibrous scaffolds enhance cell infiltration in vitro. This study compares strength and tissue ingrowth of aligned and unaligned nanofibrous scaffolds to absorbable and permanent meshes. We hypothesize that PLCL nanofibrous grafts will provide strength necessary for physiological function while serving as a scaffold to guide native tissue regeneration in vivo.

Abdominal wall defects were created in 126 rats followed by underlay implantation of Vicryl, Gore-Tex, aligned, or unaligned PLCL Nanofiber mesh. Specimens were harvested at 2, 6, and 12 wk for strength testing and 2, 12, and 24 wk for histopathologic evaluation. Specimens were graded for cellular infiltration, multinucleated giant cells (MNG), vascularity, and tissue organization. Mean scores were compared and analyzed with non-parametric testing.

The PLCL grafts maintained structural integrity until at least 12 wk and exhibited substantial tissue replacement at 24 wk. At 12 wk, only the aligned PLCL had persistent cellular infiltration of the graft, whereas both aligned and unaligned PLCL grafts showed the presence of MNG. The presence of MNGs decreased in the aligned PLCL graft by 24 wk.

The aligned PLCL nanofiber mesh offers early strength comparable to Gore-Tex but breaks down and is replaced with cellular ingrowth creating a favorable option in management of complex surgical wounds or native soft tissue defects.