INTRODUCTION: Obesity has been implicated as a risk factor for incisional hernia and diabetes has long been equated with poor wound healing.  The reported incidence of incisional hernia in bariatric surgery is as high as 20%. Previous work in our lab has shown that vanadate, a nonspecific inhibitor of protein tyrosine phosphatases increases the strength of fascial repair in Sprague-Dawley rats by 97%.  This work has opened the question: will vanadate have a similar effect in a model of diabetic compromised wound repair?  It is proposed that vanadate treated fascial/muscular abdominal wounds in obese, diabetic rats will be stronger.

METHODS: Eleven 500-750g diabetic Zucker rats were anesthetized and a midline full thickness incision made from xyphoid to pubic symphasis.  The incision at the fascial/muscular layer was closed with a running 5.0 PDS suture.  A gel contained 300 μM vanadate was placed between the fascial and skin repair in 6 rats.  The same gel containing saline was placed in the same subcutaneous/suprafascial plane of 5 saline treated Zucker rats.  At day 10 tissues from the repaired abdominal walls were harvested and strips (1 cm wide) from the superior, middle and inferior regions were tested for breaking strength.   Tissue samples from the same locations were also processed for histology.

RESULTS:  The mean wound breaking strength of vanadate treated wounds was 16.07N (± 3.04) compared to 11.13N (± 0.67) for saline controls (p < 0.003).  H&E stained sections showed similar quantities of deposited granulation tissue between the wound edges in both vanadate treated and saline treated rats.   Sirius red stained sections viewed with polarized light demonstrated in saline treated rats, fine green birefringence patterns of collagen fiber bundles, typical of young granulation tissue.  Vanadate treated wounds showed collagen fiber bundles with thicker yellow birefringence patterns which is consistent with more mature, uniform collagen fiber bundles.

CONCLUSION:  The local application of vanadate in laparotomy incisional wounds in an obese diabetic rats increases wound strength by promoting more rapid maturation of granulation tissue, characterized by more uniform organized collagen fiber bundles.  It is proposed that the direct application of vanadate at the time of surgery will increase wound strength, reducing the frequency of ventral hernias in diabetic patients.