Simvastatin and biphasic calcium phosphate affects bone formation in critical-sized rat calvarial defects

To investigate the effects of locally applied simvastatin plus biphasic calcium phosphate (BoneCeramic(r)) or collagen sponge on bone formation in critical-sized bone defects.Thirty defects of 5mm in diameter were created bilaterally with a trephine bur in the calvariae of fifteen Wistar rats. The defects were divided into five groups: group 1 - control, no treatment; group 2 (BoneCeramic(r)); group 3 (BoneCeramic(r) + 0.1mg simvastatin); group 4 (collagen sponge); and group 5 (collagen sponge + 0.1mg simvastatin). After eight weeks the animals were euthanized and their calvariae were histologically processed. Hematoxylin and eosin-stained sections were subjected to histological and histomorphometrical analyses. The area of newly formed bone was calculated and compared between groups.The greater amount of a bone-like tissue was formed around the carrier in group 3 (BoneCeramic(r) + 0.1mg simvastatin) followed by group 2 (BoneCeramic(r)), and almost no bone was formed in the other groups. Group 3 was significantly different compared to group 2, and both groups were significantly different compared to the other groups.Simvastatin combined with BoneCeramic(r) induced significantly greater amounts of newly formed bone and has great potential for the healing of bone defects.