Comparison of synthetic absorbable and non-absorbable meshes coated with platelet-rich plasma (PRP) in the treatment of abdominal hernias in rats

Hernia is a surgical lesion that has been one of the most common issues in both human and veterinary medicine throughout history, with scientists constantly pondering its treatment. In veterinary medicine, abdominal hernias can be closed with simple surgical sutures depending on the size of the defect, while larger defects may require the use of organic or synthetic grafts for closure. Synthetic grafts are the most preferred materials due to their ease of availability and application. The biggest issue with synthetic materials is recurrence and intra-abdominal adhesions. Various barrier methods have been tried to prevent these complications, but the results have been unfavorable. It has been suggested that PRP (Platelet-Rich Plasma) may be effective in preventing these complications; however, apart from wound healing, no additional contribution has been observed. This study was conducted to evaluate whether PRP coating on absorbable and non-absorbable meshes used in the treatment of abdominal hernias could prevent adhesion and promote wound healing in the defect area. The material consisted of 42 female Sprague Dawley rats weighing 250-300 grams each. The rats were randomly divided into six groups of equal numbers: Group I received absorbable mesh, Group II received absorbable mesh+PRP, Group III received non-absorbable mesh, Group IV received non-absorbable mesh+PRP, Group V served as the control, where the defect area was closed with simple interrupted sutures, and Group VI consisted of animals used to obtain PRP. After being anesthetized with rompun-ketalar, the abdominal area of the rats was shaved and disinfected with povidone iodine. A midline skin incision was made along the median line. After passing through the skin, subcutaneous tissue, and muscles, the abdominal cavity was entered. The defect area was enlarged to a size of 1x2 cm. In the first group, the defect area of the rats was closed with an absorbable mesh as an inlay. Rats in the second group were closed with a non-absorbable mesh and its PRP-coated form. Rats in the third group were closed with a non-absorbable mesh, while rats in the fourth group were closed with a non-absorbable mesh coated with PRP. The rats in the fifth group were selected as the control group, and the defect area of these rats was closed with simple interrupted sutures. Non-absorbable sutures were used for all suturing and closure of the skin. Within a 20-day follow-up period, no complications developed. On the twentieth day, all rats in the groups were euthanized using CO2 gas. A burst experiment was conducted to measure the tension in the abdominal cavity. According to the results of the experiment, the highest tensile strength was observed in the fourth group. Subsequently, the abdominal area was opened, and evaluations were made regarding adhesion formation. As a result of this observation, moderate to severe adhesions were observed in all groups where mesh was used, with fewer adhesions noted in the control group. Tensile strength testing was conducted, and tissue samples were taken for histopathological and biochemical examinations. According to the tensile strength test results, there was no statistically significant difference between the groups. The best results in terms of histopathological findings were observed in the fourth group. In this group, mild levels of mononuclear cell infiltration and edema were observed, while angiogenesis was seen at a moderate level. According to the biochemical analysis, it was observed that in the group where non-absorbable mesh and PRP were used, the levels of lipid peroxidation and the changes in antioxidant enzyme activities favored oxidants, reducing oxidative stress. In conclusion, it was observed that using non-absorbable mesh coated with PRP did not prevent adhesion but accelerated wound healing by increasing neovascularization. Therefore, it was concluded that using non-absorbable mesh coated with PRP would be appropriate when early closure of abdominal defects is desired.