Effect of St John's wort on bone formation in the orthopaedically expanded premaxillary suture in rats: a...

The aim of this study was to investigate the effect of systemic St John's wort (Hypericum perforatum) on bone formation in the expanded premaxillary suture in rats.

A total of 28 rats were randomly divided into four groups of equal numbers: control (C); only expansion (OE); St John's wort extract given only during the expansion and retention period (a total of 17 days; SJW group); and St John's wort extract given during the nursery phase before expansion (a period of 40 days), and during the expansion and retention periods (a total of 57 days; N + SJW group). After the 5 day expansion period was completed, the rats in the OE, SJW, and N + SJW groups underwent 12 days of mechanical retention, following which they were killed, and their premaxilla dissected and fixed. Histological examination was performed to determine the number of osteoclasts and capillaries, as well as the number of osteoblasts, inflammatory cell infiltration, and the amount of new bone formation.

Statistical analysis showed that the number of osteoclasts and capillaries, and the inflammatory cell infiltration, as well as new bone formation, were higher in the SJW and N + SJW groups than in the other groups. However, statistical analysis demonstrated that among these two groups, all parameters, with the exception of the number of capillaries, were higher in the N + SJW group than the SJW group.

Although more effective in long-term usage, systemic use of St John's wort hastens new bone regeneration at the premaxillary suture and may help prevent relapse after expansion.