Objective- To determine the effects of the Hydrocortisone on in vitro growth of fibrobla sts isolatedfrom the distal  aspects of the horses limbs.
Design- Experimental in vitro study.
Animals- A total of 4 Caspian miniature and 4 mixed thoroughbred horses.
Procedures- Under generalanesthesia and aseptic condition, a full thickness of skin incision was created on the lateral aspects of themetacarpal mid-third and 3 grams of subcutaneous tissue was harvested and placed on culture medium(RPMI-1640) in an incubator at 37°C in 5%C02. The Hydrocortisone was added in 3 different concentrations [treatm ent groups A (l014 g/ml) , B (100 14g/ml), and C (300 14g/ml)] into the culture medium and cellcounting was carried out after 4 days. The effects of Hydrocortisone added to control media were comparedwith a control media on fibroblast growth and viability. The data were analyzed by one way ANOVA andTukey test.
Results- There were no significant differences in fibroblast growth rate and viability percentage (p>O.05)between the groups control and A, but the groups Band C suppressed significantly the fibroblast growthand decreased viability percentage in compared with groups control and A (p<0.05), and also there were nosignificant differences between groups Band C in fibroblast growth rate and viability percentage (p>0.05).
Conclusion and Clinical Relevance- The effect of Hydrocortisone on cultured fibroblast growth isdose-dependant. Application ofthis agent can inhibit fibroblast growth; therefore it can be used for treatmentofexuberant granulation tissue and improving wound healing processes, especially in the distal limb woundsof the horses