Evaluation of the effects of isotretinoin on new bone formation after maxillary sutural expansion in rats

Isotretinoin is a drug to treat acne vulgaris in adolescents and young adults and known to cause hyperosteosis but in long-term, it can also cause demineralization of bones. Our aim was to evaluate the effects of isotretinoin on new bone formation during maxillary sutural expansion in rats. Thirty-two 8 week-old male Wistar rats were included. Isotretinoin group was treated with 7,5mg/kg isotretinoin, dissolved in 2ml/kg soybean oil via oral gavage for 57 days. Soybean group was treated with 2ml/kg soybean oil via oral gavage for 57 days. Expansion group wasn't treated with any substance. At all experiment groups, expansion was started at the 41st day and after 5 days of expansion, retention period of 12 days was established. Control group wasn't treated with any substance and no procedure was done. Animals were sacrified, their maxilla were dissected for histological evaluation. Number of osteoblasts and osteoclasts, capillaries and new bone formation intensities were evaluated on the slides centered around the suture. Differences in the number of osteoclasts and osteoblasts among the four groups were evaluated with Kruskal-Wallis test. Pair-wise comparisons were made with Mann-Whitney U test. New bone and capillary formations were scored according to intensity and evaluated with Fisher-Exact Test. Significant differences were found between four groups for osteoblasts and osteoclasts (p<0.001). In 3 experimental groups, more osteoblasts and osteoclasts were detected at a significant level than the control group (p<0.001) and there was no statistically significant difference between the experimental groups. There was a significant difference between the groups in the vascularization and new bone formation scores (p<0.001). Capillary formation and new bone formation in the isotretinoin group were found to be at a higher level than the other groups. Isotretinoin had no negative effects on maxillary sutural expansion in rats, on the contrary it enhanced new capillary and bone formation. Keywords: Bone formation, Rat, Rme