Rabbit Gingiva Research Articles

Basic fibroblast growth factor and epidermal growth factor reverse impaired ulcer healing of the rabbit oral mucosa.

The therapies for refractory ulcers on the oral mucosa are symptomatic and very unsatisfactory. We hypothesized that application of growth factors might be able to achieve successful remission of the lesion. We evaluated the effects of systemic administration and topical application of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on impaired wound healing of ulcers in the rabbit gingiva. Almost uniform round ulcers could be created on the gingiva of the rabbits by chemical injury with acetic acid. When the submandibular glands were removed or i.v. injection of cisplatin (CDDP) and peplomycin sulfate was performed before ulcer formation, healing of the ulcers took longer than in untreated rabbits. To ascertain whether or not human EGF and bFGF affect rabbit cells, we first examined the effects of EGF and bFGF on the proliferation of the cells derived from rabbit gingiva. We then applied EGF or bFGF in these impaired healing models. EGF and bFGF promoted proliferation of the fibroblasts, and EGF also promoted proliferation of the keratinocytes isolated from gingival tissue of rabbits in vitro. Systemic injections of EGF and bFGF in rabbits, which had their submandibular glands removed, and topical application of bFGF accelerated healing of ulcers created in rabbits injected with CDDP and peplomycin sulfate. The ability of bFGF to promote the healing of ulcers was much greater than that of EGF. Basic FGF may be effective for refractory oral mucosal lesions.

Specific progesterone receptors in rabbit gingiva.

The cytoplasm and nucleus of male and female rabbit gingiva and cytoplasm of rabbit oral mucosa contain receptors capable of specifically binding progesterone and promegesiooe with high affinity (Kd =2.7 × 10−9 M) and low capacity (∼10 fmol/mg protein). The binding is sensitive to heat, is destroyed by warming to 37°C for 60 min by proteolylic enzymes (pronase and trypsin), and exhibits a pattern of competition similar to that obtained with progesterone receptors from other target tissues. These results provide evidence that rabbit gingiva and buccal mucosa may function as target tissues for progestms.

Enzyme Patterns of Glycolysis in Rabbit Gingiva and Effects of pH on the Patterns

The specific activities of individual enzymes associated with glycolysis in rabbit gingiva were systematically evaluated, and the enzyme patterns at pH 7.4 were established on the glycolytic and gluconeogenic pathways. As a result, it was suggested that there was no capability for gluconeogenesis. The effects of alkaline pH values on the enzyme patterns appeared to lead to the overall stimulation of glycolysis.

Enzyme patterns of glycolysis and gluconeogenesis in rabbit gingiva and the effects of pH on the patterns

In order to clarity the enzyme patterns of the glycolytic and gluconeogenetic reactions on the, glycolytic pathway in rabbit gingiva, the conditions for the measurements of the enzyme activities were examined and established on the forward and re verse reactions in 15 enzymes associated with the glycolytic pathway. The difference of each enzyme activity tested in triethanolamine, Hepes and Tris buffers were found to bring about a respectable change of the enzyme pattern due to the kind of buffer used in the assay mixture.The enzyme patterns at pH 7.4 obtained in the present paper were as follows: 1) hexokinase and 6-phosphofructokinase were suspected to operate as the reg ulatory enzymes of the glycolytic reaction 2) The activities of triosephosphate isomerase and lactate dehydrogenase showed an approximately 10 fold difference between the forward and reverse reactions 3) The rabbit gingiva seemed to have no gluconeogenesis because the e nzyme activities of phosphoenolpyruvate carboxykinase, pyruvate carboxylase and glucose 6-phosphatase associated with gluconeogenesis were undetected.The effects of various pH levels on the enzyme patterns generall y suggested the accumulation of fructose 1, 6-bisphosphate and overall activities of glycolysis at alkaline pH values, and the accumulation of glucose 6-phosphate and the decrease in glycolytic flux at acidic pH values.

Identification of hyaluronidase activity in rabbit gingiva (author's transl)

A hyaluronidase activity was demonstrated in rabbit gingiva by determining its ability to release reactive N-acetylhexosamine group from hyaluronate. The optimum pH of the enzyme was 3.6. The enzyme was inhibited by ferric ion, iodoacetamide, and ferrous ion in the decreasing order. The enzyme was activated by protamine and poly-L-lysine. For determining the extent of polymerization of the reaction products, molar ratios of hexosamine to uronic acid were estimated before and after reduction with sodium borohydride. Comparing these vales with those calculated theoretically, it was concluded that the end product of the enzyme reaction was terasaccharide. These results clearly demonstrate that hyaluronidase exists in gingival tissue.

Comparison of fluoride toxicity between periodontal pathogenic bacteria and rabbit gingiva

The effects of topical fluoride treatment on the metabolic activity of explants of rabbit gingival tissue in vitro and of gingival tissue in situ were compared with the antibacterial effects of fluoride on suspected plaque periodontal pathogens. Exposure of the gingival explants to fluoride reduced the incorporation of both radioactively labelled proline and thymidine, indices of protein synthesis and cell division, respectively. The degree of depression varied directly with concentration and exposure time. Comparison of these data with that of previously reported bacteriological studies showed that gingival tissue metabolism was profoundly depressed by fluoride applications at or near the in-vitro threshold for preventing the growth of suspected periodontal pathogens. The effects of in-vitro exposure to fluoride on the subsequent uptake of labelled thymidine were compared in gingival tissue explants versus periodontal pathogens. Similar toxic potency was observed. Determination of the effects of fluoride on intact gingival tissue in situ, however, provided strong evidence for the existence of a broad and useful difference in toxicity of fluoride between bacteria and intact gingival tissue, thereby providing support for the possible therapeutic use of topical fluorides in the prevention and treatment of periodontal disease. The basis of the difference in toxicity appeared to be the integrity of the epithelial layer of the gingiva.

Enzymatic properties of phosphogluconate dehydrogenase in rabbit gingiva.

Enzymatic properties of phosphogluconate dehydrogenase in rabbit gingiva.

A new model for the study of transport of [ 14C]-diphenylhydantoin through the gingival crevicular tissues in the rabbit

Radioactive molecules can be monitored as they pass from the confines of the gingival crevice into the crevicular tissues and subsequently into the blood of rabbit. Initial studies employed this technique to trace [ 14C]-diphenylhydantoin (DPH). Evidence suggests that DPH has an affinity for the crevicular tissues and that this tissue may be rate limiting in drug intake into serum. Administration of systemic non-radioactive DPH appeared to eliminate this effect. In all cases substantial amounts of [ 14C]-DPH were observed in crevicular tissue two hours after termination of the incubation. Levels of systemically administered DPH were not different in the crevicular tissue portion of rabbit gingiva and the entire gingiva.

The microvasculature of the rabbit gingiva as affected by progesterone: an ultrastructural study.

The microvasculature of the rabbit gingiva as affected by progesterone: an ultrastructural study.

Ultrastructural localization of antibody to an antigen applied topically to rabbit gingiva.

After four weeks of repeated irrigations of intact labial gingival sulci of rabbit mandibular incisors with horseradish peroxidase (HRPO), antiperoxidase antibody was demonstrated ultra‐structurally in the cistemae of the endoplasmic reticulum of some plasma cells in the gingival lamina propria. Antibody was found also in all cell types of the plasmacytic series in the regional lymph nodes. It was present in the basement membrane and the adjacent connective tissue and in the extraneous cell coat material of crevicular epithelial cells. Continued topical irrigations eventually caused an allergic type inflammatory response which, if allowed to resolve, would reappear fifteen minutes after irrigating the gingival sulci with HRPO.

Dermal-epidermal interactions. Cultivation of embryonic rabbit gingiva and studies of heterotypic tissue recombinants on the chick chorio-allantoic membrane

Gingiva and dorsal skin from 25-day embryonic New Zealand white rabbits were excised and explanted as xenografts on the CAM for periods up to 10 days. Organ cultures retained their characteristic histodifferentiation and indicated continued growth and development. Recombinants of trypsin-dissociated palate and skin epithelium and adjacent dermis illustrated advances in development. In all cases homotypic tissue isolates of epithelium or dermis did not retain their phenotypes. Recombinants of heterotypic isolated tissues indicated aninstructuve influence by the specific dermis upon the epithelium.

The role of inflammation and sensitization on antigen penetration in rabbit gingiva.

Journal of PeriodontologyVolume 42, Issue 12 p. 796-803 The Role of Inflammation and Sensitization on Antigen Penetration in Rabbit Gingiva H. M. Dick, H. M. Dick Associate Professor, Faculty of Dentistry, University of Alberta, Edmonton, Alberta, Canada.Search for more papers by this authorJ. R. Trott, J. R. Trott Professor, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada.Search for more papers by this author H. M. Dick, H. M. Dick Associate Professor, Faculty of Dentistry, University of Alberta, Edmonton, Alberta, Canada.Search for more papers by this authorJ. R. Trott, J. R. Trott Professor, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada.Search for more papers by this author First published: 01 December 1971 https://doi.org/10.1902/jop.1971.42.12.796Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume42, Issue12December 1971Pages 796-803 RelatedInformation

Nerve plexuses in the oral mucosa

Oral nerve plexuses were studied in the mucosa of the tongue, hard palate, cheek and gingiva of rabbits, cats and monkeys. Whole thickness methylene blue preparations, frozen sections of tissue impregnated with silver and photographic reconstructions were used to assess the topographical arrangement and density of nervous plexuses. In the various regions a coarse submucous plexus and a much finer subepithelial network were identified, and these were associated with sensory nerve terminations. Plexus formations were found to have greatest density in the dorsum of the tongue, hard palate and gingiva, particularly in the anterior part of the mouth. Myelinated somatic fibres predominated in the plexuses but, from a consideration of nerve fibre diameters, it was concluded that autonomic fibres contribute to the formation of oral nerve networks. The findings lend further support to the view that sensory discrimination largely depends on a complex pattern of nerve impulses reaching higher centres.