Downregulation of basic fibroblast growth factor is associated with femoral head necrosis in broilers

Femoral head necrosis (FHN) is a metabolic cartilage disease of rapidly growing broilers. The aim of the present study was to investigate the role of basic fibroblast growth factor (bFGF) in the apoptotic processes associated with FHN. Broilers were selected and categorized based on clinical examination in 3 groups: healthy, femoral head separation, or femoral head separation with growth plate lacerations. Hematoxylin and eosin staining showed fewer chondrocytes in the resting zone of the growth plates when FHN occurred. Moreover, the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay revealed a significant increase in chondrocyte apoptosis. Furthermore, immunohistochemical assays and real-time quantitative PCR analysis demonstrated a decline in bFGF expression. In addition, reduced Bcl-2 mRNA expression was observed along with a corresponding increase in Bax and caspase-3 mRNA expression in FHN samples. There was a correlation between bFGF protein expression and the proportion of TUNEL-positive cells and a correlation between bFGF mRNA expression and expression of Bax, and caspase-3. The results of the study suggested that the expression of bFGF was reduced in the process of chondrocyte apoptosis, which could play an important role in the pathogenesis of FHN in chickens.