PARACRINE REGULATORS IN DISTRACTION OSTEOGENESIS (pilot study)

Purpose – to evaluate effect of protein extracted from lengthened skeletal muscles on callus formation in dogs after tibia lengthening using Ilizarov method.

Materials and methods. The authors studied properties of distraction callus formation in three groups of dogs after tibia lengthening by Ilizarov method. In the first group (n = 10) distraction was achieved at a rate of 1 mm in four stages during 28 days. In the second (n = 4) and third (n = 4) groups distraction was done at a rate of 1.5 mm in 6 stages per day within 20 days. Mean lengthening value in all groups amounted to 14,64±0,67% of the overall segment length. At the 10th day of distraction the authors introduced to animals of the second group into anterior tibial and gastrocnemius muscles of the lengthened segment at callus level the extract of sarcoplasmic proteins in amount of 1.5ml based on 1 mg of lyophilizate per 1 kg of body weight (protein concentration in injectate amounted to 30±2 gr/l). Animals in the third group received natural saline solution in the same manner. Extract consisted of lyophilized sarcoplasmic proteins harvested from anterior tibial muscle of animal at 14th day of lengthening by Ilizarov method (rate of 1 mm per day in 4 stages). Extraction was performed according to patented method (Russian Federation patent for invention №2476234) by consecutive muscle proteins sedimentation in KCl solutions of varied ionic strength. The lyophilizate was sterilized after obtaining and dissolved in normal saline solution prior to introduction.

Results. Radiographic signs of anatomically solid callus in the first group were observed in the average at 33±1 day of fixation; in the second group – at 24±2 day; in the third group – at 39±3. Difference in mean values of fixation in animals of second group as compared to first and third groups was significant (р = 0,04). After extract introduction the animals of the second group demonstrated a greater growth of γ-globulins and α2-globulins fraction volumes.

Conclusion. Skeletal muscles of limb segment lengthened by Ilizarov method produce specific factors that impact the process of distraction osteogenesis.