Background: There are limited data on the effects of GBP on bone and no data for PGB. Some data suggest that there is a significant influence of sex hormone balance on the susceptibility of bone to antiepileptic drug-induced bone loss.
Methods: Forty-eight male Wistar rats were divided into six groups that were subjected to two surgeries, sham (noORX) or real orchidectomy (ORX), and were fed three diets, a SLD, a SLD enriched with GBP or a SLD enriched with PGB. Dual energy X-ray absorptiometry was used to measure the bone mineral density.
The concentrations of bone turnover markers were assayed. The femurs were biomechanically tested.
Results: Significant reductions in bone mineral density, weight and biomechanical strength were observed in ORX animals. GBP or PGB exposure did not cause significant alterations in bone mineral density or biomechanical strength.
No changes in bone turnover markers were observed, except for RANKL. A significant increase was found in the ORX GBP and ORX PGB groups.
Within the orchidectomized animal group, RANKL levels were significantly higher in the ORX PGB group than in the ORX GBP group. Conclusions: Because neither GBP nor PGB affected bone mineral density or mechanical bone strength, both of these antiepileptic drugs could be considered drugs with lower risks to bone health.
A shift in RANKL levels indicates that the effects of GBP and PGB on osteoclast activity may be dependent on the hormonal status of animals.