Comparative study of shrinkage, inflammatory response and fibroplasia in heavyweight and lightweight meshes.
OBJECTIVE
In this manuscript, the authors describe an animal study comparing shrinkage, inflammatory response and fibroplasia in heavyweight (HW-PP) and lightweight polypropylene (LW-PP) meshes.


METHODS
Both meshes were fixed on abdominal fascia of 25 Wistar rats (epifascial onlay placement). They were killed at 7, 28 and 90 days to measure the prostheses. Histological analysis was performed with hematoxylin-eosin for cellular counting and immunohistochemistry to measure collagen types I and III.


RESULTS
The authors found that the LW-PP mesh presented greater median shrinkage than HW-PP mesh at 7 (P = .036), 28 (P = .674) and 90 days (P = .038) postoperatively. There were more neutrophils on LW-PP mesh (P = .008) at 7 days, gradually diminishing in both prostheses. Lymphocytes were similar between the implants at 7 days, diminishing about 50 % on LW-PP mesh (P < .001) at 90 days. Macrophages and giant cells diminished on LW-PP and increased on HW-PP meshes (P < .001). Collagen I/III ratio presented a progressive, almost fivefold rise at 90 days, on both mesh types (P < .001). The collagen I/III ratio was similar between LW-PP and HW-PP meshes at the three times studied.


CONCLUSIONS
It is concluded that LW-PP showed more shrinkage than HW-PP mesh at 7 and 90 days, despite the fact that HW-PP presented more lately foreign body reaction. The collagen I/III ratio was similar between the prostheses and increased during the postimplant period.
Programa de Pós-Graduação em Cirurgia, Universidade Federal do Rio Grande do Sul (UFRGS), Ramiro Barcelos Street 2400, 90035-003, Porto Alegre, RS, Brazil, clinicazogbi@gmail.com.
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D034861:Abdominal Wall / Q000473:pathology* / Q000502:physiology; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D011126:Polypropylenes / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar; D013526:Surgical Mesh / Q000009:adverse effects*
D015415:Biomarkers; D024042:Collagen Type I; D024061:Collagen Type III; D011126:Polypropylenes