Niacin Exacerbates Methyl Prednisolone-Induced Bone Changes in Growing Rats

Positive role of niacin on serum lipid profile of rats treated with glucocorticoids (GCs) has been reported. This study aims to evaluate effect of niacin on bone changes in GC-induced dyslipidemic rats. A number of 28 growing rats divided into four groups and treated as control, Methyl prednisolone (MP) group (3.5 mg/kg five days a week, SC); MPN group (MP + niacin 200 mg/kg/day orally) and MPA group (MP + alendronate 0.03 mg/kg/day, SC). After 4 weeks, serum lipid profile and histomorphometric parameters including trabecular width (Tb.Wi), trabecular separation (Tb.Sp) and number (Tb.N), bone area/tissue area (B.Ar/T.Ar) and osteoid thickness (O.Th) in metaphyseal side of growth plate of femoral head were determined. Obvious dyslipidemia and decreased B.Ar/T.Ar and O.Th were observed in MP group. Niacin alleviated dyslipidemia, however MPN rats had appreciably lower Tb.N and higher Tb.Sp as compared to MP group. Alendronate had a moderate positive effect on bone changes. Although niacin effectively ameliorates GC-induced dyslipidemia in growing rats, it may exacerbate bone changes.