Fig 1.
Macroscopic image of the biomaterials after implant into the experimental animal. (A) DM+ implant, (B) PP implant presoaked in either CHX or allicin-CHX solutions.
Table 1.
Scoring system utilized to evaluate the implants at the moment of the euthanasia.
Fig 2.
Diagram showing the harvesting and processing of the tissue samples to carry out the macroscopic, microbiological and histological evaluation of the different implants.
Fig 3.
In vitro agar well diffusion test.
Representative images of the inhibition zones after 24 h of incubation at 37°C by the (A) CHX and (B) allicin-CHX solutions utilized to soak the PP meshes. (C) Sterile saline used as control did not provoke bacterial growth inhibition. (D) Mean diameter of the inhibition zones (mm). The results are expressed as the mean ± standard error of the mean for 5 samples. The allicin-CHX solution provoked significantly wider inhibition halos than the CHX treatment. #: saline vs CHX and allicin-CHX (p<0.001); ф: CHX vs saline and allicin-CHX (p<0.001).
Fig 4.
Appearance of the different meshes after 14 days of implantation and Sa contamination. (A, B) DM+ implants showing thick fibrous encapsulation (*), seroma formation (▶) and the presence of dispersed purulent material (→) associated with the mesh anchorage, while the main body of the implant remains clean. (C, D) PP + CHX implants showing similar behavior to the previous ones, with the exceptions of a more intense vascularization and total mesh integration into the host tissue. (E, F) PP + allicin-CHX implants show large amounts of purulent material (→) covering different areas of the implant surface.
Table 2.
Viable CFU per mesh fragment (2 x 1 cm) of the Sa-contaminated implants.
Fig 5.
Tissue integration of the implanted biomaterials.
Panoramic compositions (Masson´s trichrome staining, x50) and light microscopy (hematoxylin-eosin, x100) micrographs of the different study groups. (A, B) The DM+ implants were partially integrated in the host tissue and showed a dense neoformed connective tissue containing inflammatory cells and angiogenesis (→) below the mesh. (C, D) The PP + CHX implants were fully integrated and exhibited cavities (*) in the neoformed tissue containing non-drained seroma and showed loose connective tissue surrounding the mesh filaments with angiogenesis (→). The PP + allicin-CHX implants displayed loose connective tissue infiltrating the mesh with different-sized abscesses (▶) and angiogenesis (→). f: mesh filaments; ic: intraperitoneal cavity; m: muscle; nt: neoformed tissue; ss: subcutaneous side.
Fig 6.
Bacterial adhesion to the implant surface.
SEM micrographs (x2000) and Sa immunolabeling (x400) of the different study groups. (A-C) The DM+ implants showed no presence of bacteria in either the neoformed connective tissue or in the mesh surface. (E-G) The PP + CHX implants did not exhibit bacteria in the neoformed tissue, apart from the single exception of one specimen (F), which yielded bacteria (→) following mesh sonication. (I-K) The connective tissues of the PP + allicin-CHX implants were free of bacteria, although microorganisms (→) were found inside and surrounding the abscesses. The negative controls of the (D) DM+, (H) PP + CHX and (L) PP + allicin-CHX implants showed no immunostaining. f: mesh filaments.
Fig 7.
RAM-11 immunostaining (x200) of the (A) DM+, (B) PP + CHX, and (C) PP + allicin-CHX implants showing the presence of labeled macrophages (→) in the neoformed tissue. (D-F) Negative controls of the DM+ (D), PP + CHX (E) and PP + allicin-CHX (F) implants showing no immunostaining. (G) Positive cell percentages recorded after 14 days of implant. The results are expressed as the mean ± standard error of the mean for the total of micrographs counted (7 specimens per study group, 10 micrographs per specimen). The lower percentage of RAM-11 positive cells recorded for the PP + allicin-CHX implants was not statistically significant.