Incisional wounds 15 mm long were induced surgically in the back skin of young adult Wistar rats. They were sutured and used as an experimental model in the therapeutic evaluation of daily applications of 0.5 mL of silver nitrate (SN) at 0.01, 0.1 or 1.0% w/v aqueous solution, or 0.5 g silver sulphadiazine (SSD) over a 10-day period. Control wounds received deionized water only. The silver preparations were not toxic but SN did stain the hair and superficial layers of the stratum corneum. The wounds remained microbiologically clean. Wounds exposed to SN (0.1 or 1.0%) or SSD healed more rapidly than controls. From about the fourth day of treatment, we noted a more rapid exteriorization of sutures, improved wound closure and an earlier loss of scabs and wound debris. Silver treatment appeared to reduce the inflammatory and granulation tissue phases of healing and enhance epidermal repair. Silver from SN was deposited as silver sulphide in extrafollicular hair shafts and superficial aspects of the skin and wound debris but not at deeper levels. Silver uptake was four-fold higher in damaged skin than in intact tissue. SSD was absorbed by intact and wounded skin but the silver did not precipitate as silver sulphide and its localization in the tissue is not known. Uptake of silver from SN or SSD was associated with changes in the concentrations of zinc and calcium in the skin. Zinc levels were depressed during the inflammatory and proliferative phases of healing and then increased. Zinc concentrations had normalized by 10 days when wound healing was achieved. Calcium levels remained higher than normal throughout the observation period. The mechanism of action of silver in advancing wound healing in the rat is unclear. Its ability to reduce the inflammatory and granulation phases of healing, and to invoke metallothionein production and influence metal ion binding are possibly important.

Incisional wounds 15 mm long were induced surgically in the back skin of young adult Wistar rats. They were sutured and used as an experimental model in the therapeutic evaluation of daily applications of 0.5 mL of silver nitrate (SN) at 0.01, 0.1 or 1.0% w/v aqueous solution, or 0.5 g silver sulphadiazine (SSD) over a 10-day period. Control wounds received deionized water only. The silver preparations were not toxic but SN did stain the hair and superficial layers of the stratum corneum. The wounds remained microbiologically clean. Wounds exposed to SN (0.1 or 1.0%) or SSD healed more rapidly than controls. From about the fourth day of treatment, we noted a more rapid exteriorization of sutures, improved wound closure and an earlier loss of scabs and wound debris. Silver treatment appeared to reduce the inflammatory and granulation tissue phases of healing and enhance epidermal repair. Silver from SN was deposited as silver sulphide in extrafollicular hair shafts and superficial aspects of the skin and wound debris but not at deeper levels. Silver uptake was four-fold higher in damaged skin than in intact tissue. SSD was absorbed by intact and wounded skin but the silver did not precipitate as silver sulphide and its localization in the tissue is not known. Uptake of silver from SN or SSD was associated with changes in the concentrations of zinc and calcium in the skin. Zinc levels were depressed during the inflammatory and proliferative phases of healing and then increased. Zinc concentrations had normalized by 10 days when wound healing was achieved. Calcium levels remained higher than normal throughout the observation period. The mechanism of action of silver in advancing wound healing in the rat is unclear. Its ability to reduce the inflammatory and granulation phases of healing, and to invoke metallothionein production and influence metal ion binding are possibly important.

Bananas are reported to have an antipeptic ulcer effect, however, the beneficial action can be affected by many factors, including the variety. Our study was undertaken to investigate the antipeptic ulcer effect of the Palo and Horn varieties of banana, grown and consumed in the northeast of Thailand. Indomethacin and acetic acid-induced gastric lesions in rats were employed as models of peptic ulcer disease. The lengths of gastric lesions in the glandular part of the stomach were measured for the assessment of the protective effect of bananas. The healing effect was studied by histological examination of the ulcerated area. The lesions in rats treated with the extract of banana were significantly less dominant than those of the control. The average length of total lesions of rats treated with an extract of Palo or Horn bananas at a dose of 1.0 g/kg/d for 3 days prior to indomethacin administration were 4.47+/-1.2 and 1.87+/-0.44 mm, respectively, whereas those observed in the control rats were 14.56+/-2.43 mm. In the ulcer-healing model, only the Hom-banana-extract-treated group showed a beneficial effect which manifested as a milder degree of histological change than that of the indomethacin-induced-chronic-ulcer control group. However, in acetic acid-induced ulcers, the histological changes of every group were similar. The present findings indicate that bananas of different varieties have varying antipeptic ulcer effects. The extracts of Palo and Hom bananas have a prominent gastroprotective effect, whereas only the extract of Hom banana had an observed ulcer-healing effect.

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