TEM (15000× magnification) of the femoral heads from each experimental group.

<p>Normal control group (A): Osteogenic cells were round or oval, large in size and rich in organelles. Model control group (D): Osteoblasts were flat with swollen mitochondria with degenerated vacuoles and relatively few rough endoplasmic reticula (rER) were present in the cytoplasm. Negative pressure group, week 4 (B) and week 8 (C): Osteoblasts were round or oval, the cells gradually increased in size and the number of rER increased in the cytoplasm and formed membranous tubes with attached ribosomes. In addition, there were numerous mitochondria. Nuclear staining was light and the structure was intact. Core decompression group, week 4 (E) and week 8 (F): ER and mitochondria numbers in the cytoplasm of the osteoblasts were increased, but increases were to a lesser extent compared with the negative pressure group at various time points.