Effect of jog stress at fracture site on local basic fibroblast growth factor

Lin QIAO; Shuxun HOU; Shuming ZHANG; Min LIU; Daming SUN

ABSTRACT

BACKGROUND:

Some researches demonstrate that jog stress at fracture part can promote formation of callus, but molecular biological mechanism of jog stress on fracture healing is still unclear.

OBJECTIVE:

To study the effect of jog stress at fracture site on basic fibroblast growth factor(bFGF)at broken parts.

DESIGN:

Randomized controlled animal study.

SETTING:

Department of Orthopaedics,General Hospital of the Second Artilleryman of Chinese PLA;Departments of Orthopaedics and Pharmacy,the First Affiliated Hospital of General Hospital of Chinese PLA.MATERIALSThe experiment was carried out in the Animal Laboratory,the First Affiliated Hospital of General Hospital of Chinese PLA and the 8th Laboratory,Academy of Military Medical Sciences of Chinese PLA from March 2003 to April 2004.A total of 72 healthy purebred New Zealand rabbits,of general grade,5-6 months old,weighing 2.5-3.0 kg,were provided by Animal Center of Academy of Military Medical Sciences of Chinese PLA.All rabbits were randomly divided into jog group and fixation group with 36 rabbits in each group.And then,every 6 rabbits in both groups were respectively observed at 6 time points,including 7,14,21,28,42 and 56 days.

METHODS:

All animals were anesthetized with ketamine and sumian xinji.Fixation needle was rotated into 3,3.5,5.5 and 6 cm below platform of tibia,respectively,and then external fixators were installed.Chuck which was located at 1.5 cm from internal cortical bone and 4.5 cm below platform of tibia crossly cut off tibia.Fracture space was 2.0 mm and 2.5 mm in the fixation group and jog group,respectively.Animals in the fixation group were fixed with unilateral external fixator to dissect replace fracture part.In addition,animals in the jog group cut off their bone,fixed,and moved 0.5 mm to axis along central staff of external fixator.Animals were able to freely walk and external fixator was slightly shaken based on body mass of animal.Furthermore,all animals were sacrificed at 7,14,21,28,42 and 56 days after operation.According to the center of fracture part,samples in 1 cm length were cut,divided and fixed for 12 hours.Quantitative analysis of bFGF and colorized intensity were detected with immunohistochemical stain and JVC imaging analytic system at 7,14,21,28,42 and 56 days after operation.MAIN OUTCOME

MEASURES:

①Detecting colored intensity of bFGF;②quantitative analysis of bFGF.

RESULTS:

A total of 72 rabbits were involved in the final analysis bFGF could express in interstitial cells,vascular endothelial cell,osteoblast,chondroblast and osteocyte plasma.At 14,21 and 28 days after operation,positive indexes of bFGF protein in the jog group were 1.98±0.14,2.04±0.12 and 2.13±0.17,respectively,which were obviously higher than those in fixation group(1.59±0.14,1.68±0.15,1.63±0.27,P＜0.05).

CONCLUSION:

Jog stress can increase numbers of bFGF at fracture part and promote fracture healing.