Surgical stress influences cytokine content in autologous conditioned serum.

REASONS FOR PERFORMING STUDY No recommendations have been made regarding the relative timing of blood collection for autologous conditioned serum (ACS) preparation and surgical procedures. OBJECTIVES 1) To identify effects of surgical stress on cytokine levels in ACS, 2) identify haematological markers for prediction of cytokine production in ACS and 3) investigate the necessity for specialised ACS containers when preparing a cytokine-rich serum. STUDY DESIGN Experimental in vitro study. METHODS Blood was drawn from 15 stallions admitted for elective castration preoperatively and 22-24 h post operatively and incubated in ACS containers and plastic vacutainer tubes containing Z Serum Clot Activator. Concentrations of interleukin (IL)-1 receptor agonist (IL-1Ra), IL-10, IL-1β, tumour necrosis factor (TNF)-α, insulin-like growth factor (IGF)-1 and transforming growth factor (TGF)-β were determined in all serum samples and compared between preparation methods and sampling time by ANOVA. Changes in cytokine levels induced by incubation, defined as delta cytokine, were calculated by subtracting the baseline levels from the levels in incubated samples. Based on post operative serum amyloid A (SAA), horses were grouped into 'mild', moderate' and 'marked' surgical stress; delta cytokine levels in post operative samples were compared between these groups by ANOVA. RESULTS Delta IGF-1 was significantly lower in post operative samples compared with preoperative. Horses in the 'marked' surgical stress group had significantly lower delta IL-1Ra and delta TGF-β than the 'moderate' group and significantly lower delta IGF-1 than the 'mild' group. No association between cytokine levels and haematology variables were identified. Cytokine levels were comparable between serum prepared in blood tubes and in specialised ACS containers. CONCLUSIONS Surgical stress influences the cytokine content in ACS. Useful predictors of cytokine production in ACS were not identified. Specialised ACS containers may not be necessary for preparation of a cytokine-rich serum.