Cranio‐caudal differences in granulation tissue formation: an experimental study in the rat

Abstract

This study examined potential regional differences in the deposition of granulation tissue in cellulose sponges placed in the dorsum of rats. Four cellulose sponge implants, 10 x 10 x 5 mm in size, two in cranial and two in caudal positions, were used to induce granulation tissue formation in the back of the rat. A cranio-caudal difference in connective tissue formation was assessed from 1 to 24 weeks after implantation. Granulation tissue ingrowth, measured histomorphometrically, was enhanced at 2 weeks and the surrounding capsule was thinner from 1 to 3 weeks in implants located in the cranial part of the back. In the cranial position, the number of fibroblasts, assessed semiquantitatively, was higher and the ratio of inflammatory cells to fibroblasts lower at 2-3 weeks. Also, the ratio of hydroxyproline content to total nitrogen content was higher after the first week in cranial specimens. Thus, a distinct cranio-caudal difference in the proliferative phase was observed. These results show the obvious practical considerations underlying the need for randomization or comparison between implants from exactly corresponding cranio-caudal locations.

Importance of defining experimental conditions in a mouse excisional wound model

“…Many previous wound healing studies using a murine dorsum excisional wound model have not specified the detailed locations of the wounds. As craniocaudal differences in granulation tissue formation in a rat model have been reported, wound location, especially craniocaudal position for a murine wound healing model, should be carefully determined as well. Thus, we compared wound healing differences in the mouse for craniocaudal position wound healing kinetics and splint maintenance for silicone splints placed to minimize contraction.…”

Effects of topical insulin on second-intention wound healing in the red-eared slider turtle (Trachemys scripta elegans) – a controlled study

“…After removing the biopsy piece the wounds had well-formed circular walls and reached the subcutaneous skeletal muscles and blood vessels. The wounds were made symmetrically because previous studies in rats have shown differential healing of cutaneous wounds in the same animal depending on their cranial-caudal location [22]. …”

Cutaneous Wound Healing in the Cat: A Macroscopic Description and Comparison with Cutaneous Wound Healing in the Dog

“…This wound was used to evaluate first intention wound healing by LDPI, wound breaking strength, and histologic analysis. Because previous studies in rats had shown differential healing of cutaneous wounds based on their cranial–caudal location on the trunk, 7 the wounds were created in the same location on each animal regardless of differences in body size. The most cranial wound was located just caudal to the caudal border of the scapula and the most caudal wound was located just cranial to the ilial wing.…”