Summary

Intra-articular injections of autologous peripheral blood stem cells (PBSC) combined with hyaluronic acid (HA) demonstrated superior histological outcomes in articular cartilage regeneration compared to control and HA-only groups in a sheep model, suggesting potential therapeutic efficacy for cartilage repair.

Abstract

Introduction

The purpose of this study was to assess histologically whether intra-articular injections of autologous peripheral blood stem cells (PBSC) resulted in better regeneration of articular cartilage.

MATERIALS & METHODS:
Fifteen sheep were equally divided into three groups. An 8mm diameter full thickness articular cartilage defect was created, followed by subchondral drilling into the left stifle joint. Group A (Control group) underwent surgery only; Group B (HA group) received 2 mL of hyaluronic acid (Ostenil®, TRB Chemedica AG, Germany) post-surgery; and Group C (PBSC+HA group) received injections of 2 mL PBSC along with 2 mL HA post-surgery. Three injections were administered: on the day of surgery and 1 weekly injection for 2 consecutive weeks. PBSC in Group C were harvested via apheresis one month before surgery. All animals were sacrificed at 24 weeks post-surgery. The stifle joints were harvested and examined macroscopically and histologically, utilizing the ICRS Visual Assessment Scale II. Statistical analysis was conducted using SPSS, with comparative analysis being two-tailed, and the level of statistical significance set at p < 0.05.

Results

All animals in the study survived throughout its duration. Higher ICRS II scores indicate better regenerated cartilage. Group C showed a statistically significant difference compared to Group A (p=0.014) and Group B (p=0.016), highlighting its superior regenerative outcomes.

Discussions:
Macroscopic evaluation showed cartilage regeneration in all groups, but incomplete filling of chondral defects due to the short joint harvesting duration. Histological images from PBSC-treated group depicted cartilage most closely resembling normal cartilage, consistent with prior clinical study findings.­ It is also observed that Group C has more Collagen type II stains indicating better cartilage formation as compared to Groups A and B.

Conclusion

Intra-articular injections with PBSC resulted in better articular cartilage regeneration based on histological evaluation.