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This study aimed to evaluate femoral perfusion using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for two weeks after the simultaneous initiation of electrical stimulation (ES) and steroid treatment in a steroid-induced osteonecrosis (ON) model. A single dose of methylprednisolone was injected into 14 rabbits. Seven rabbits underwent ES (ES group), and seven rabbits did not (control group). DCE-MRI was performed before steroid administration and 1, 5, 10, and 14 days after steroid administration. Regions of interest were set in the bilateral proximal femora. The enhancement ratio, initial slope, and area under the curve were analyzed. These parameters were evaluated after steroid administration in each group and between the two groups, and the ratios of ON in both groups were compared. In the control group, the minimum values of all parameters decreased significantly after steroid administration (P < 0.05), but in the ES group, the parameters did not decrease. In the ES group, all parameter values were significantly increased on the 10th and 14th days (P < 0.05). All parameter values in the ES group were significantly higher than those in the control group on the 14th day (P < 0.05). In the control group, ON was detected in three of five rabbits (in three of ten femora). In the ES group, ON was not detected. These results suggest that increased femoral blood flow elicited by ES may be related to ON prevention after steroid administration. [ABSTRACT FROM AUTHOR]

Background and purpose Prevention of osteonecrosis after corticosteroid administration would be important. We examined the potential of vitamin E ( α-tocopherol) to reduce the incidence of corticosteroid-induced osteonecrosis in an animal model. Methods Japanese white rabbits were divided into 2 groups; the control group was fed a normal diet and the experimental group was fed α-tocopherol-supplemented diet in which α-tocopherol (600 mg/kg diet) was added to the normal diet. To induce osteonecrosis, high-dose methylprednisolone acetate (MPSL) (20 mg/kg body weight) was injected once into the right gluteus medius muscle of all rabbits. 4 weeks after the injection of MPSL, the presence or absence of osteonecrosis of bilateral femurs was examined histopathologically. The tocopherol/cholesterol ratios were calculated. The plasma levels of thiobarbituric acid-reactive substances (TBARS) were measured. Results Alpha-tocopherol-supplemented diet reduced the incidence of osteonecrosis, which developed in 14 of 20 rabbits in the control group and 5 of 21 rabbits in the experimental group (p = 0.004). The tocopherol/cholesterol ratio was higher in the experimental group than in the control group after the α-tocopherol administration. The plasma TBARS level was lower in the experimental group than in the control group at 4 weeks after the MPSL administration. Interpretation Our findings may offer a new approach for the prevention of corticosteroid-induced osteonecrosis. [ABSTRACT FROM AUTHOR]

Nontraumatic osteonecrosis (ON) of the femoral head is known to be one of the major complications after organ transplantations. Although the precise mechanism is still uncertain, the administration of glucocorticoid (GC) has been considered to play an important role in the occurrence of ON. To elucidate the genetic factors involved in this pathogenesis, we analyzed single nucleotide polymorphisms (SNP) in the genes for the GC receptor (GR), CYP3A4, cAMP-responsive element binding protein-binding protein (CBP), and nuclear receptor co-activator 2 (NCoA2). Among the patients examined, A/G alleles of the CBP gene were demonstrated in 32.4% of those with ON, but in only 14.6% of those without ON (P = 0.018). No relationships were observed between the SNPs of GR, CYP3A4, and NCoA2 genes and the occurrence of ON. These results indicate that the genetic polymorphism of the CBP, which is one of the essential factors exerting the biological effects of GC, may affect susceptibility to steroid-induced ON in patients after renal transplantation. [ABSTRACT FROM AUTHOR]