Platelet-rich plasma inhibits Wnt/ß-catenin signaling in rabbit cartilage cells activated by IL-1ß.

OBJECTIVE: Platelet-rich plasma (PRP) has been reported to alleviate degenerative pathological damage to joint cartilage. This study aimed to investigate the effect of PRP on Wnt/ß-catenin signaling in rabbit chondrocytes. METHODS: Using 3-month-old New Zealand white rabbits, PRP was prepared from venous blood, and chondrocytes were cultured from knee joint cartilage and identified by staining for type II collagen and proteoglycan. The effects of PRP on chondrocyte viability were measured. The chondrocytes were divided into 5 groups: control, IL-1ß, PRP (100-fold dilution), Dkk-1 (100ng/mL) and Dkk-1+PRP. The IL-1ß, PRP, Dkk-1 and Dkk-1+PRP groups were treated with interleukin (IL)-1ß (50µL, 10µg/mL) for24h. Chondrocyte morphology was observed by electron microscopy. Levels of carboxy terminal peptide (CTX-II) and cartilage oligomeric matrix protein (COMP) in culture media were measured by ELISA. Wnt-1, ß-catenin and GSK-3ß mRNA and protein expression were determined by RT-PCR and western blot respectively. RESULTS: PRP enhanced chondrocyte proliferation. Chondrocytes in the IL-1ß group showed ultrastructural abnormalities that were less pronounced in the PRP, Dkk-1 and Dkk-1+PRP groups. CTX-II and COMP concentrations were higher in the IL-1ß group than in the control, PRP, Dkk-1 and Dkk-1+PRP groups (P<0.05). The IL-1ß group had higher mRNA and protein Wnt1 and ß-catenin levels and lower GSK-3ß levels than the control, PRP, Dkk-1 and Dkk-1+PRP groups (P<0.05). CONCLUSION: PRP may protect chondrocytes activated by IL-1ß via inhibiting Wnt/ß-catenin signaling.

The effects of sclerostin antibody plus parathyroid hormone (1-34) on bone formation in ovariectomized rats.

Previous studies have demonstrated the effects of sclerostin antibody (Scl-Ab) and parathyroid hormone (1-34, PTH) on healing in osteoporosis; however, reports about the combined effects of Scl-Ab plus PTH on osteoporosis are limited. This study was designed to investigate the impact of combined treatment with Scl-Ab and PTH on osteoporosis healing in ovariectomized (OVX) rats. After bilateral ovariectomy, 12 weeks were allowed to pass for the establishment of standard conditions for osteoporosis in animal models. The rats then randomly received a vehicle (control), Scl-Ab (25 mg/kg body weight, twice weekly), PTH (60 µg/kg, three times per week) or PTH plus Scl-Ab until death at 12 weeks. The blood and distal femurs of the rats were harvested for evaluation. The results of treatment for osteoporosis were evaluated by serum analysis, histology, microcomputed tomography (micro-CT) and biomechanical tests. Results from this study indicated that PTH + Scl-Ab had stronger effects on the prevention and treatment of osteoporosis than either of the monotherapies in OVX rats. The PTH + Scl-Ab produced the strongest effects on bone volume fraction (BV/TV), bone trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular spacing (Tb.Sp), bone mineral density (BMD) and strength of distal femurs and increased the levels of procollagen type I N­terminal propeptide (PINP) and osteocalcin. In contrast, monotherapy with PTH or Scl-Ab showed no differences between treated groups in the assessment of the metaphysis of contralateral femurs by histology, serum, biomechanical tests and micro-CT. These results seem to indicate that Scl-Ab plus PTH has an additive effect on osteoporosis in OVX rats.