RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of organic gallium and gallium chloride on bone metabolism and their therapeutic effect against tretinoin-induced osteoporosis in rats.</p><p><b>METHODS</b>Rat models of osteoporosis was established with intragastric administration of tretinoin at the daily dose of 85 mg/kg for 15 days and randomized into control, organic gallium and gallium chloride groups. After administration of the corresponding treatments (none for the control group) for 4 weeks, the changes of the indices for osteoporosis were evaluated through biochemical and pathological approaches.</p><p><b>RESULTS</b>Tretinoin induced obvious changes in bone structure and contents of bone calcium and other elements, causing also significantly increased tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (AKP), which suggested the development of osteoporosis. Administration of organic gallium and gallium chloride treatments increased the bone density, bone cortex thickness and the percentage of bone trabecula, and Ga, Ca, P contents in the femur and teeth, but lowered the activity of TRAP and AKP, suggesting decreased bone conversion rate. Compared with gallium chloride, organic gallium required smaller dose with better safety to produce better therapeutic effect.</p><p><b>CONCLUSION</b>Organic gallium can be safe and effective for treatment of tretinoin-induced osteoporosis in rats.</p>