Esterified hyaluronic acid improves cartilage viability in experimental tracheal reconstruction with an auricular graft.

OBJECTIVE: The aim of this study was to determine the efficacy of esterified hyaluronic acid (HYAFF) on the vitality of auricular cartilage grafts used for tracheoplasty, with respect to macroscopic and microscopic parameters. STUDY DESIGN: Prospective, controlled. SETTING: Academic research laboratory. SUBJECTS AND METHODS: The study included 14 New Zealand rabbits acquired specifically for the study. The rabbits were divided into two groups: the control group, in which free cartilage grafts were not exposed to any materials or additional procedures (n = 7), and the hyaluronic acid (HA) treatment group, in which auricular grafts and anastomosis lines were covered with HYAFF (n = 7). Free auricular cartilage grafts used for the reconstruction of experimentally created tracheal defects were anastomosed extraluminally. All the rabbits were sacrificed two months post surgery. Samples were collected and examined histopathologically. The sections were stained with hematoxylin-eosin, Masson's trichrome, and inducible nitric oxide synthase (iNOS) and examined under a light microscope. RESULTS: Fibrosis and cartilage mass significantly differed between the control and HYAFF group (P < 0.05). Immunohistochemical examination showed that more chondrocytes stained with iNOS in the control group than in the HYAFF group, according to histologists' observations. CONCLUSION: HYAFF catalyzed wound healing with less fibrous tissue formation, had chondroprotective and stimulatory effects on chondrocyte metabolism, and decreased nitric oxide production and apoptosis via improving the nourishment of free auricular cartilage grafts, subsequently preventing hypoxia and oxidative stress, particularly in the early postimplantation period.

Comparison of efficacy of ivermectin and doramectin against mange mite (Sarcoptes scabiei) in naturally infested rabbits in Turkey.

The authors used 14 New Zealand rabbits (5 naturally infested rabbits and 9 in-contact rabbits) for Sarcoptes scabiei treatment in this study. Signs, such as itchy ears, eyes, tail and abdominal skin, alopecia and pyoderma, were considered to be the cause of these disorders. Infested rabbits were grouped according to the intensity of S. scabiei infestation (low, medium and high). Each group was then divided into two subgroups; in one subgroup the rabbits received ivermectin (1%) and, in the other, doramectin (1%). All subgroups received a subcutaneous injection at a dosage of 400 microg/kg body weight every 80 h on three occasions. On day 28 after commencing the treatment, all the rabbits in the first two groups had recovered completely. Although both drugs were applied at the same time and at the same dose, the third group (high degree of infestation), revealed, both microscopically and macroscopically, that ivermectin has more rapid effect than doramectin. Treatment was effective in all groups.

Viability of crushed and diced cartilage grafts wrapped in oxidized regenerated cellulose and esterified hyaluronic acid: an experimental study.

OBJECTIVES: The objective of this study was to investigate the viability of diced/crushed cartilage grafts wrapped in esterified hyaluronic acid (HYAFF) and oxidized regenerated cellulose (Surgicel) with respect to macroscopic and microscopic parameters. STUDY DESIGN: Experimental study. METHODS: A total of 10 New Zealand rabbits were acquired for the study. Cartilage grafts were harvested from both ears, with the ventral and dorsal perichondrial layers dissected off. There were six comparison groups in this experimental study: 1) bare, diced cartilage, 2) diced cartilage wrapped in Surgicel, 3) diced cartilage wrapped in HYAFF, 4) bare, crushed cartilage, 5) crushed cartilage wrapped in Surgicel, 6) crushed cartilage wrapped in HYAFF. Six cartilage grafts were inserted into the six subcutaneous pockets of the same animal. All the rabbits were sacrificed at the end of 2 months, the samples were collected, and the total specimen was examined histopathologically. The sections were stained with hematoxylin-eosin and Masson trichrome stain and examined under light microscopy. RESULTS: There was a significant difference among the bare, diced cartilage, the Surgicel, and the HYAFF groups with respect to fibrosis, chronic inflammation, cartilage mass, and vascularization. A significant difference was observed among the bare, crushed cartilage, Surgicel, and HYAFF groups with respect to fibrosis, chronic inflammation, and cartilage mass. There was no significant difference among the three groups regarding vascularization. CONCLUSIONS: This study suggests that wrapping cartilage grafts with Surgicel grossly reduces cartilage viability and the regeneration potential of the chondrocytes, leading to fibrosis formation. On the other hand, hyaluronic acid promotes cartilage integrity and survival, thus increasing clinical predictability and avoiding the need for overcorrection.