Effect of zoledronate on the expression of vascular endothelial growth factor-a by articular chondrocytes and synovial cells: an in vitro study

Zoledronate promotes ECM degradation and apoptosis via Wnt/β-catenin

This study examined the potential mechanism of zoledronate on interleukin (IL)-1β-induced temporomandibular joint osteoarthritis (TMJOA) chondrocytes, using IL-1β-induced rabbit immortalized mandibular condylar chondrocytes cultured with zoledronate. Cell viability, apoptosis, mRNA, and protein expression of relevant genes involved in extracellular matrix (ECM) degradation, apoptosis, and Wnt/β-catenin signaling were examined. The involvement of the Wnt/β-catenin signaling was examined using Wnt/β-catenin inhibitor (2-(4-(trifluoromethyl)phenyl)-7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidin-4-ol (XAV-939)) and activator lithium chloride (LiCl). Aggrecan and type II collagen were downregulated by zoledronate, especially with 100 nM for 48 h (p < 0.01), consistently with the upregulation of A disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) (p < 0.001), matrix metalloprotease-9 (MMP-9) (p < 0.01), caspase-3 (p < 0.001) and downregulation of proliferating cell nuclear antigen (PCNA) (p < 0.01). The apoptotic rate increased from 34.1% to 45.7% with 100 nM zoledronate for 48 h (p < 0.01). The effects of zoledronate on ADAMTs4 (p < 0.001), MMP-9 (p < 0.001), caspase-3 (p < 0.001), and PCNA (p < 0.01) were reversed by XAV-939, while LiCl increased caspase-3 expression (p < 0.01). In conclusion, zoledronate enhances IL-1β-induced ECM degradation and cell apoptosis in TMJOA chondrocytes. Wnt/β-catenin signaling might be involved in this process, but additional studies are necessary to determine the exact involvement of Wnt/β-catenin signaling in chondrocytes after zoledronate treatment.

Effects of bisphosphonate treatment on mandibular condyle tissues of temporomandibular joint: A stereological study

INTRODUCTION

Although the adverse effects due to the use of bisphosphonates, such as bisphosphonate-induced osteonecrosis of the jaw, are reported previously, whether adverse events of the temporomandibular joint related with bisphosphonate treatment have been still unclear. Therefore, the aim of this study is to evaluate the effects of BP treatment on the condylar tissues of the temporomandibular joint due to fibrous cartilage, hyaline cartilage and bone-specific differences in rat animal models.

MATERIAL AND METHOD

A total of 12 adult Wistar-Albino rats, weighing from 250 to 300 g were included to the study. The animals were randomly divided into two groups. 0.1 mg/kg Zoledronic Acid were administrated to the animals intraperitoneally in the experimental bisphosphonate group for 60 days. Rest of the animals left as healthy control. All the animals were sacrificed at the end of 60 days. Two condyles were obtained from each animal and total 12 condyles were included to histological analysis in each group. The fibrous cartilage volume, hyaline cartilage volume and bone volume of the condyle were calculated using Cavalieri method. Statistical analysis was performed with Turcosa software.

RESULTS

There is a statistically significant difference of fibrous cartilage (P = 0.003) and bone volume between groups (P = 0.002). However, mean hyaline cartilage volume does not statistically differ between groups (P = 0.47). Bone volume and firbrous cartilage volume were increased in bisphosphonate group than control.

CONCLUSION

According to our study results Zoledronic Acid treatment did not affect the hyaline cartilage volume however fibrocartilage volume and bone volume were increased when the animals received ZA intraperitoneally for 60 days.