The Effect Of Injury And Training After Injury On The Expression Of VEGF And BFGF

Patella-patellar tendon junction injury is a kind of chronic injury of the quadriceps tendon, the patellar tendon and the extensor aponeurosis around the attachment of the patella. It is normally caused by heavy long-term specific training of athletes of football, basketball, volleyball and jumping events.This experiment investigates the effect of training after injury on the expression of two factors:the Vascular Endothelial Growth Factor (VEGF) at the bone-tendon junction and the Basic Fibroblast Growth Factor (bFGF). Together with the variances of histomorphological and other related indices, the degree of local damages can be evaluated, and the characteristics of pathological changes at the bone-tendon junction are depicted. It is meaning for early diagnosis and treatment of such injuries and further improvement of the athletic performances.Subjects and methods:Fourteen New Zealand white female rabbits are randomly divided into three groups:NL Group (needle and cyclic loading, n=7), ND Group (needle, n=7), and CON Group (controls, n=7). For each single rabbit, its left and right hind limbs are respectively treated in NL and ND Group. In ND Group, the patellar tendons of the right hind limbs of rabbits are stuck by needles at the inferior margins of the patella. In NL Group, the left hind limbs of rabbits are stimulated by cyclic loading after needle sticks. The electronic stimulation intensity is adjusted to make the force of each knee extension equal to30%of its largest capacity. The total stimulation time is24hours. After four weeks’training, rabbits are harvested. Tissues are then collected, followed which decalcification, conventional dehydration, transparency, paraffin embedding and sections are done. HE and Safranin0staining are used to observe the Histological changes at the patella-patellar tendon junction, meanwhile, immunohistochemical staining is used to count and analyze the expression of VEGF and bFGF according to the images under the microscope. Results and analyses: At the end of the four weeks’training, compared with CON Group, tendon fibers of the specimens in NL and ND Group are arranged in disorder, cross-linked and merged. Besides, in NL and N Group, tendon cell nuclear becomes rounded and deeply stained, aligned in chains and aggregated together, the’tidal mark’rises and becomes unclear or disappears. Island groups of hyaline cartilage can be observed in the fibrocartilage region. All the above phenomena indicate successful modeling of NL and ND Group. Meanwhile, the density of tendon cell and the thickness of fibrocartilage are increased statistically in NL and ND Group. The expression level of Proteoglycan at the bone-tendon junction in NL Group is higher than that ND Group and CON Group, hut there is no significant difference between ND Group and CON Group. After modeling, the expressions of VEGF and bFGF at the bone-tendon junction are increased in both NL and ND Group (with the expression of bFGF higher in NL Group than ND Group), which is obviously different compared with CON Group in statistic.Conclusions:①The Injuries caused by needle do exist at the end of four weeks, which indicates the difficulty of recovering in patella-patellar tendon junction.②The training after injury did not significantly promote healing processes or inhibit it.③Both acute injury and training after injury can lead to higher expression level of VEGF and BFGF at the bone-tendon junction, indicates that the repair of tissue is progressing,hasn’t recover to the level before injury.