Objective: To screen for the differentially expressed genes in steroid-induced osteonecrosis of the femoral head (ONFH) by gene microarray.
Methods: The femoral head tissue of ONFH was harvested from 3 patients with steroid-induced ONFH, aged 25, 31, and 38 years, respectively. Normal tissue was harvested from a 26-year-old male remains contributor. HE staining of the specimens was performed for observing the histology manifestation; the total RNA was extracted for measuring the purity; cDNA probe was synthesized by reverse transcription, and then were hybridized as the cDNA microarray for scanning of fluorescent signals and differentially expressed genes in the tissues.
Results: HE staining of normal tissue showed complete unit composed of lamellar bone, continuous and complete lamellar bone with a concentric arrangement around blood vessels, and normal bone cells in the trabecular bone lacuna. In ONFH tissue, adipose tissue increased in the medullary cavity, with increased fat cells filling in the medullary cavity and extruding capillary, and with decreased bone cells in the bone trabecula, which had deeply-stained nuclear chromatin, pyknotic or cracking nucleus, and even bone cells disappeared in the part of the bone lacuna, and trabecular bone became thin, sparse, interrupt, reduced area in visual field/unit. Total RNA extraction electrophoretogram displayed clear bands of 28S and 18S, and the brightness ratio of the 28S:18S was 2:1, indicating good total RNA quality. And 44 genes were differentially expressed, and there were 28 up-regulated genes and 16 down-regulated genes, including cell/organism defense genes, cell structure/motility genes, cell division genes, cell signaling/ cell communication genes, cell metabolism genes, gene/protein expression genes, and unclassified genes.
Conclusion: The analysis of the gene expression profile of steroid-induced ONFH can provide evidence for the pathogenesis of ONFH.