Abstract

ObjectiveIschemic osteonecrosis of the femoral head (ONFH) in piglets results in an ischemic injury to the immature articular cartilage. The molecular changes in the articular cartilage in response to ONFH have not been investigated using a transcriptomic approach. The purpose of this study was to perform a genome-wide transcriptomic analysis to identify genes that are upregulated in the immature articular cartilage following ONFH.MethodsONFH was induced in the right femoral head of 6-week old piglets. The unoperated femoral head was used as the normal control. At 24 hours (acute ischemic-hypoxic injury), 2 weeks (avascular necrosis in the femoral head) and 4 weeks (early repair) after surgery (n = 4 piglets/time point), RNA was isolated from the articular cartilage of the femoral head. A microarray analysis was performed using Affymetrix Porcine GeneChip Array. An enrichment analysis and functional clustering of the genes upregulated due to ONFH were performed using DAVID and STRING software, respectively. The increased expression of selected genes was confirmed by a real-time qRTPCR analysis.ResultsInduction of ONFH resulted in the upregulation of 383 genes at 24 hours, 122 genes at 2 weeks and 124 genes at 4 weeks compared to the normal controls. At 24 hours, the genes involved in oxidoreductive, cell-survival, and angiogenic responses were significantly enriched among the upregulated genes. These genes were involved in HIF-1, PI3K-Akt, and MAPK signaling pathways. At 2 weeks, secretory and signaling proteins involved in angiogenic and inflammatory responses, PI3K-Akt and matrix-remodeling pathways were significantly enriched. At 4 weeks, genes that represent inflammatory cytokines and chemokine signaling pathways were significantly enriched. Several index genes (genes that are upregulated at more than one time point following ONFH and are known to be important in various biological processes) including HIF-1A, VEGFA, IL-6, IL6R, IL-8, CCL2, FGF2, TGFB2, MMP1, MMP3, ITGA5, FN and Col6A1 were upregulated in the immature articular cartilage following ONFH. A qRTPCR analysis of selected genes confirmed the upregulated expression observed in the microarray analysis.ConclusionImmature articular cartilage responds to ONFH by the upregulation of genes involved in hypoxic stress response, angiogenesis, matrix remodeling and inflammation. This study provides novel insights into the multi-faceted role of immature articular cartilage, with inflammation as a key component, following ONFH in piglets.

Highlights

  • Legg-Calvé-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis of the femoral head (ONFH), which can produce a severe flattening deformity of the femoral head [1,2]

  • Induction of ONFH resulted in the upregulation of 383 genes at 24 hours, 122 genes at 2 weeks and 124 genes at 4 weeks compared to the normal controls

  • Immature articular cartilage responds to ONFH by the upregulation of genes involved in hypoxic stress response, angiogenesis, matrix remodeling and inflammation

Read more

Summary

Introduction

Legg-Calvé-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis of the femoral head (ONFH), which can produce a severe flattening deformity of the femoral head [1,2]. This deformity can lead to a debilitating osteoarthritis of the hip joint as early as the third decade. The ischemic damage is followed by increased vascularization of the cartilage, fibrocartilage formation and hypertrophy over time [7,8,9] These findings in LCPD patients suggest that the immature articular cartilage undergoes active pathophysiological changes in response to ONFH. In order to better understand the role of immature articular cartilage following ONFH and to devise novel therapeutic approaches to prevent early onset osteoarthritis following ONFH, the molecular changes in the immature articular cartilage must be assessed

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call