Electron microscopic immunochemical localization of actin in fibroblasts in healing skin and palate wounds of beagle dog

A histologic evaluation of various stages of palatal healing following subepithelial connective tissue grafting procedures: a comparison of eight cases

BACKGROUND

It is often necessary to procure tissue from the same area of the palate in cases where connective autogenous grafting procedures are warranted due to limitations caused by anatomical features. The purpose of this study was to determine whether the length of time between a first procurement and a second would have any bearing on the quality of tissue available for recipient sites.

METHODS

Eight patients requiring more than one grafting procedure underwent surgery at baseline and again at various intervals ranging from 6 weeks to 11 months. Specimens were taken from the palate and evaluated microscopically, and photographs were taken for purposes of visual comparison.

RESULTS

The 6.9- to 7.7-week specimens exhibited complete reepithelialization. The lamina propriae were composed of a cellular proliferation of fibroblasts with loosely arranged collagen deposition and an occasional thin vascular channel. However, remodeling of the wound appeared complete in the specimens removed at the 9-week interval and beyond. The lamina propria was, in general, composed of thick, dense, interlacing bundles of collagen. Small-caliber blood vessels were interspersed throughout the fibrous element.

CONCLUSION

Reharvesting of tissue performed earlier than at 9 weeks may result in poorer autogenous graft quality due to indications that remodeling of the connective tissue is still progressing and not as mature as specimens noted at weeks 9 to 47.

A histological and ultrastructural study of wound healing after vomer resection in the beagle dog

Trauma to the vomer during cleft-palate surgery may impair anterior-posterior growth of the premaxilla and maxilla. The vomer was resected via a palatal flap in four 42-day-old beagle pups; four unoperated dogs served as controls. One experimental and one control animal was perfused at 2, 4, 8 and 12 weeks after surgery and specimens from the vomer-premaxillary suture and from the vomer at the level of the mid-palate were processed for light and electron microscopy. Measurements of maxillary casts showed retardation in anterior-posterior growth and development of an anterior cross-bite in all but one of the experimental animals. Microscopic examination of the healing wound showed granulation tissue and contractile fibroblasts, which were more numerous at the premaxilla-vomer suture than at the posterior site. Developing elastic fibres were also seen. Quantitation of fibroblasts revealed that 25-50 per cent in the control suture had the characteristics of contractile cells, but this reached 75 per cent in the resected group. These cells together with the elastin many constitute a system that retards anterior-posterior growth and leads to cross-bite.