Morphological comparative study of knot-induced foreign giant cells infiltration and fibrosis in differential level of mice abdominal wall

Objective Knot-induced inflammatory response can be seen in percutaneous extracorporeal knotting for laparoscopic inguinal inner ring closure in children. The present study aimed to investigate the correlation between knot-induced foreign giant cells infiltration and fibrosis in mice abdominal wall. Methods 28 mice were targeted; three vertical and parallel incisions were created in abdominal wall in same Balb/C mice, followed by saturation with 1 mm stitch using MERSILK® non-absorbable suture. The knots were respectively resided in subcutaneous, intramuscular and extra peritoneal layer in abdominal wall. The knot segments in each group were harvested at day 14 and day 28 post-operation. HE, IHC staining and Masson staining were conducted to investigate the location of knots in each group, foreign giant cells infiltration and collagen deposition around knots in each group. Results H&E staining indicated that the knot was made accurately subcutaneous, intramuscular and extra peritoneal space in abdominal wall. The immunohistochemistry staining indicated less foreign giant cells infiltration and collagen deposition in extra peritoneal space in abdominal wall. On the contrary, more foreign giant cells infiltration and increased collagen production could be noted in subcutaneous layer. Conclusion Our studies show the correlation between knot-induced long term of inflammatory responses and differential knot location in mice abdominal wall in mice. Knot in extra peritoneal space induced slight foreign inflammation and fibrosis in abdominal wall, compared with other subcutaneous and intramuscular layers. Our study further supported that knotting in extracorporeal knotting procedure for inguinal hernia in children, has potential to cause slight knot-induced inflammation. Key words: Abdominal wall; Depth; Knot; Inflammation response; Foreign giant cells; Fibrosis