A stereological analysis of fibrosis and inflammatory reaction induced by four different synthetic slings

Abstract

OBJECTIVES To analyse quantitatively, using stereological methods, the density of the collagen fibres induced by four types of sling materials, and verify by a histopathological analysis the corresponding inflammatory reaction, as fibrosis secondary to sling implantation is considered responsible for restoring urethral support and re‐establishing continence in women with stress urinary incontinence, and new synthetic materials that promote adequate fibrosis with the least intensity and duration have been proposed to substitute the aponeurotic sling. MATERIALS AND METHODS The study comprised 70 isogenic white Wistar rats divided into three groups: group A (30 rats) had 8 × 4 mm strips of silicone and porcine small intestine submucosa (SIS) implanted in the abdominal subcutaneous tissues; group B (30 rats) had 8 × 4 mm strips of polycaprolactone and polylactic acid copolymers and monofilament polypropylene (PLP) implanted the abdominal subcutaneous layer; while a control group of 10 rats had dissection and suturing with 5/0 Nylon in the abdominal subcutaneous layer, as used to fix the strips in the other rats. Picro‐Sirius staining was used to assess collagen fibres, and haematoxylin‐eosin for the histopathological study. At 7, 30 and 90 days after surgery, 10 rats from each group were killed and assessed. RESULTS After 7 days all the materials induced a moderate inflammatory reaction that did not differ from that in the control group. At 30 days there was no difference between the control and polycaprolactone and polylactic acid copolymers, having the least inflammatory reaction. PLP and silicone produced a moderate inflammatory reaction, while the porcine SIS induced a more intense reaction. At 90 days there was a more intense inflammatory reaction in polycaprolactone and polylactic acid copolymers than before but it was less than with PLP and silicone, which again were no different. During this period the inflammatory reaction induced by SIS was greater. The stereological analysis indicated that collagen fibres induced by polycaprolactone and polylactic acid copolymers and PLP were less dense (61% and 65%, respectively), and significantly less than with silicone (85%) and SIS (86%). CONCLUSION PLP was the best nonabsorbable material as it induced a less intense inflammatory reaction than the other tested materials. As porcine SIS was completely absorbed the intense fibrosis induced is useful, as it is exclusively responsible for the urethral support later after surgery.

Polypropylene mesh and the host response

“…The amount and type of collagen production stimulated by different materials may vary owing to their respective properties and environment [10,11]. Using an animal model, de Almeida et al noted that at day 60, both Prolene® (1,500-μm pores) and Marlex® (PP, 600-μm pores) induced a similar inflammatory response.…”

Impact of the structure of polypropylene meshes in local tissue reaction: in vivo stereological study

“…The picro-sirius stain was chosen because of its fine results in collagen staining in previous studies using similar methods [4,12].…”

Pubovaginal sling materials and their outcomes

“…[45] Histopathological analyses by Wiedemann and Otto [53] indicated that growth factors contained in the small intestinal submucosa (SIS) most likely result in the significant reduction in donorrecipient immunogenic reaction and scar tissue formation seen with this type of PVS. Thiel et al [54] analyzed the fibrotic and inflammatory reaction caused by four different sling materials in 70 Wistar rats. The authors found that the amount of inflammation and collagen fibers was higher in SIS compared to polycaprolactone, polylactic acid copolymers, and monofilament polypropylene mesh.…”