Histomorphometric study of diazinon on growth plate of rat

Bone is a hard and dynamic tissue, which continually undergoes remodeling process. Longitudinal growth of bone is mediated by growth plate that is a cartilage structure at the end of long bones. During puberty, along with the closure (ossification) of growth plate, the longitudinal growth of bone will stop. Diazinon is one of the widely used organophosphorus pesticides that have been known to cause damage to the cells and tissues of the body by enhancing oxidative stress. Due to the dynamism and active process, bone and growth plate tissues are suitable models to investigate the effect of diazinon on bone development and bone growth. The aim of this study was to investigate the effects of diazinon on the epiphyseal growth plate width (including the proliferating cells zone and hypertrophy cells zone) of immature rat. This is an experimental study. This study was performed on 12 immature male in Ferdowsi University of Mashhad in May 2014, Wistar rats that randomly divided into 2 groups: control group and diazinon group. All treatments were done by oral gavage during 28 days. The animals were sacrificed on day 28 and left femur bones were removed for histomorphometric studies of epiphyseal growth plate width. Assessments were done by ImageJ software, version 1.40g (Wayne Rasband, NIH, USA) and the significance of the results were performed by ANOVA analysis and Tukey’s test. Epiphyseal growth plate width of diazinon group was significantly reduced (P=0.0126) in compared to control group. This reduction was associated with reduced of width of the proliferating zone (P=0.0001) and increased width of the hypertrophy zone (P=0.0166). Diazinon leads to reduction in the Epiphyseal growth plate width of immature male rats. Therefore it could be a factor in the impairment of bone longitudinal growth and premature closure of the growth plate.