Therapeutic effect of alendronate in an experimental temporomandibular joint osteoarthritis

Effects of alendronate on cartilage lesions and micro-architecture deterioration of subchondral bone in patellofemoral osteoarthritic ovariectomized rats with patella-baja

BACKGROUND

Patellofemoral osteoarthritis (PFJOA) is a subtype of knee OA, which is one of the main causes of anterior knee pain. The current study found an increased prevalence of OA in postmenopausal women, called postmenopausal OA. Therefore, we designed the ovariectomized rat model of patella baja-induced PFJOA. Alendronate (ALN) inhibits osteoclast-mediated bone loss, and has been reported the favorable result of a potential intervention option of OA treatment. However, the potential effects of ALN treatment on PFJOA in the ovariectomized rat model are unknown and need further investigation prior to exploration in the clinical research setting. In this study, the effects of ALN on articular cartilage degradation and subchondral bone microstructure were assessed in the ovariectomized PFJOA rat model for 10 weeks.

METHODS

Patella baja and estrogen withdrawal were induced by patellar ligament shortening (PLS) and bilateral ovariectmomy surgeries in 3-month-old female Sprague-Dawley rats, respectively. Rats were randomly divided into five groups (n = 8): Sham + V; OVX + V, Sham + PLS + V, OVX + PLS + V, OVX + PLS + ALN (ALN: 70 μg/kg/week). Radiography was performed to evaluate patellar height ratios, and the progression of PFJOA was assessed by macroscopic and microscopic analyses, immunohistochemistry and micro-computed tomography (micro-CT).

RESULTS

Our results found that the patella baja model prepared by PLS can successfully cause degeneration of articular cartilage and subchondral bone, resulting in changes of PFJOA. OVX caused a decrease in estrogen levels in rats, which aggravated the joint degeneration caused by PFJOA. Early application of ALN can delay the degenerative changes of articular cartilage and subchondral bone microstructure in castrated PFJOA rat to a certain extent, improve and maintain the micrometabolism and structural changes of cartilage and subchondral bone.

CONCLUSION

The early application of ALN can delay the destruction of articular cartilage and subchondral bone microstructure in castrated PFJOA rat to a certain extent.

Effect of intra-articular injection of a hyaluronic acid-alendronate conjugate on post-traumatic osteoarthritis induced by destabilization of the medial meniscus in rats

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by pain and cartilage damage. Intra-articular (i.a) viscosupplementation with hyaluronic acid (HA) is frequently used for the management of OA. Preclinical studies have reported that bisphosphonates (BPs) may have a therapeutic potential to slow down or reverse the progression of OA. Among these, alendronate (ALN) has demonstrated chondroprotective effects in both in vitro and vivo experiments. This study evaluated the effects of a novel alendronate-hyaluronic acid (ALN-HA) conjugate on an OA in vivo model induced by medial meniscus destabilization (DMM). DMM surgery was performed on the knees of Sprague Dawley rats that received, after four weeks, one intra-articular (i.a.) injection of: (1) ALN-HA; (2) HA; (3) sodium chloride (NaCl). Sham-operated rats were used as control. Allodynia was assessed by Von Frey test. Joint degeneration was evaluated eight weeks after treatment by micro-computed tomography (micro-CT), histology, and immunohistochemistry. Collagen cross-linked C-telopeptides (CTX-I and CTX-II) serum levels were determined by ELISA. Paw withdrawal threshold increased in ALN-HA group when compared to rats treated with NaCl or HA. Micro-CT did not show differences between ALN-HA, HA and NaCl groups. ALN-HA injection produced significant improvements in articular cartilage degeneration showing an OARSI score lower than those of HA and NaCl, and reduced matrix metalloproteinase (MMP)-13, MMP-3, interleukin-6, vascular endothelial growth factor and Caspase-3 expression. CTX-I was reduced after ALN-HA treatment when compared to NaCl. Our results indicate that i.a. use of ALN after conjugation with HA limits OA development and progression in the rat DMM model, and may lead to the development of novel therapeutic strategies in OA management.

Changes in the Subchondral Bone, Visfatin, and Cartilage Biomarkers after Pharmacological Treatment of Experimental Osteoarthritis with Metformin and Alendronate

Subchondral bone that has intense communication with the articular cartilage might be a potential target for pharmacological treatment in the early stages of osteoarthritis (OA). Considering the emerging data about the role of adipokines in the pathogenesis of OA, the administration of drugs that influence their level is also intriguing. Metformin and alendronate were administered in mice with collagenase-induced OA (CIOA) as a monotherapy and in combination. Safranin O staining was used for the assessment of changes in subchondral bone and articular cartilage. Before and after treatment, serum levels of visfatin and biomarkers of cartilage turnover (CTX-II, MMP-13, and COMP) were assessed. In the current study, the combined administration of alendronate and metformin in mice with CIOA led to the protection against cartilage and subchondral bone damage. In mice with CIOA, metformin led to a decrease in visfatin level. In addition, treatment with metformin, alendronate, or their combination lowered the level of cartilage biomarkers (CTX-II and COMP), while the level of MMP-13 was not influenced. In conclusion, personalized combination treatment in OA according to clinical phenotype, especially in the early stages of the disease, might lead to the identification of a successful disease-modifying therapeutic protocol in OA.