IN-VITRO AND IN-VIVO EFFECTS OF ACTIVATED MACROPHAGE SUPERNATANT ON DISTAL LIMB WOUNDS OF PONIES

Objective-To determine whether monokines produced by activated rabbit peritoneal macrophages can inhibit development of exuberant granulatio n tissue formation in distal limb wounds in ponies. Design-Randomized block. Animals-5 castrated male ponies, 2 to 6 years-old and weighing 140 to 190 kg. Procedure-In vitro activity of cell-free rabbit periton eal macrophage supernatant was determined after incubation of fibrobla sts from the flank and the distal portion of limbs of horses and ponie s. Tritiated thymidine was then added, and after reincubation, radioac tivity was measured. After creation of a 4-cm(2), full-thickness wound on the mid dorsal aspect of each metacarpus and metatarsus of each po ny, in vivo activity of the macrophage supernatant was evaluated. Biop sy specimens were collected at random sites near a border of each woun d at 4, 6, and 10 weeks after creation of the wounds. Treatment effect s were evaluated on the basis of presence of exuberant granulation tis sue requiring excision, number of times that excision was required, to tal area of the wound, epithelialized area, area of granulation bed, a nd histologic evaluation of the biopsy specimens. Results-The macropha ge supernatant effectively inhibited proliferation of equine fibroblas ts in vitro. No significant in vivo treatment effects were found among the 4 treatment groups. Conclusion and Clinical Relevance-Monokines f rom stimulated rabbit peritoneal macrophages may have potential for im proving wound healing in horses and ponies because of their effective inhibition in vitro of equine fibroblast proliferation.