Effects on rat skin of exposure to saline and aqueous solutions of antibiotics and chlorhexidine.
Plastic chambers were glued to the dorsal skin of rats and were sealed after being filled with either distilled water, saline, an aqueous antibiotic mixture or aqueous chlorhexidine. The chambers were inspected at 24 h intervals and replenished. Groups of rats were killed at 24, 48 and 72 h; the chamber removed and the underlying skin excised and examined by light microscopy. The degree of dermatitis was assessed by means of an index of inflammation derived by scoring epidermal and dermal markers of inflammation. The results indicate that the antibiotic solution produced significantly less dermatitis compared with other treatments at each time interval studied. In general, epidermal ballooning and vesiculation occurred initially in the basal and prickle cells, but by 72 h the damaged cells were often replaced by intact keratinocytes, even though the skin was still immersed. Epidermal hyperplasia, as manifested by acanthosis and hyperkeratosis, was frequently present at 72 h.