Ultrastructural and histomorphometric alterations of rat jaw bones after experimental induction of lathyrism.

The aim of this study was to investigate the effect of beta-aminopropionitrile (beta-APN), present in Lathyrus sativus (L. sativus) seeds consumed in drought prone areas, on the maxillary and mandibular bones of rats.Eighteen rats were used; they were divided into experimental group (12 rats) and a control group (6 rats). In the experimental group, lathyrism was induced by a once daily subcutaneous administration of beta-APN at a dose of 5mg in 0.4ml distilled water per 100g of body weight for 40 days. The specimens were examined histologically, histomorphometrically and ultrastructurally.Histopathological examination of lathyritic rats showed that both mandible and maxillae were significantly affected. Irregular bone trabeculae with wide medullary cavities and abundant marrow spaces were observed. Focal resorptive areas lined with osteoclasts were also present. Histomorphometric analysis showed a decrease in the area percentage of bone in lathyritic rats as compared to the control. This decrease was statistically significant only in the mandible (p=0.018). Moreover, a significant increase in the number of osteoclasts (p=0.014, 0.012) and resorptive bays (p=0.013, 0.002) was detected in the maxillae and mandible of the experimental group, respectively. Ultrastructurally, there was a significant difference in the microarchitecture of the collagen fibres in lathyritic rats compared to the control. The collagen fibres in the lathyritic group appeared disorganized, fewer in number and more spaced.This study provided evidence for lathyritic disturbances in bone architecture. These disturbances are likely to affect mineralization and bone strength as well.