Protection of inflammatory osteoblasts in neonatal rats using catalpol from the root of rehmannia glutinosa / 中国组织工程研究

ABSTRACT

BACKGROUND: Studies have shown that abnormal osteoblast metabolism may cause abnormal subchondral bone mineralization in knee osteoarthritis. OBJECTIVE: To verify the effects of catalpol from the root of Rehmannia glutinosa on osteoblast proliferation and drug toxicity, and the anti-inflammatory protective effect on inflammatory osteoblasts induced by lipopolysaccharide. METHODS: (1) Osteoblasts from newborn Sprague-Dawley rats were primarily extracted, cultured, and passaged. The activity and proliferation of osteoblasts were determined by observing the morphology of osteoblasts alkaline phosphatase staining and staining of mineralized nodules. (2) Cell counting kit-8 (CCK-8) method was used to observe the effect of different concentrations of catalpol from the root of Rehmannia glutinosa on osteoblast activity. (3) Different concentrations of lipopolysaccharide (0, 10, 20, 40, 80, 160 mg/L) were used to induce inflammatory osteoblasts in fetal rats. CCK-8 method was used to verify the best concentration. (4) The experiment was divided into three groups: blank group, model group, low-, medium- and high-concentration catalpol groups. Inflammatory osteoblasts were induced by lipopolysaccharide at 80 mg/L, and then treated for 8 hours. CCK-8 method was used to observe the effect of different concentrations of catalpol on inflammatory osteoblasts. The study protocol was approved by the Medical Ethics Committee of Liuhe District People’s Hospital in Nanjing. RESULTS AND CONCLUSION: When osteoblasts were cultured to the fourth generation, followed by alkaline phosphatase staining, black grey granules were found in the cytoplasm of the positive cells, and the morphology of the cells was irregular. When the concentration of catalpol was lower than 1 mg/L, it had no significant effect on osteoblasts; when it was higher than 10 mg/L, it had a significant effect on the proliferation of osteoblasts but no drug toxicity (P < 0.05). When the concentration of lipopolysaccharide was higher than 80 mg/L, there was a significant trend of inflammatory damage to osteoblasts (P < 0.01). Therefore, 80 mg/L was selected as the best injury concentration in this experiment. When the concentration of catalpol from the root of Rehmannia glutinosa was lower than 1 mg/L, it had no significant protective effect on the inflammatory response of osteoblasts (P < 0.05); when it was higher than 10 mg/L, it had significant protective effect on the inflammatory response of osteoblasts (P < 0.05). Therefore, when the concentration of catalpol from the root of Rehmannia glutinosa reaches a certain level, it has no toxic effect on osteoblasts, promotes proliferation, and has anti-inflammatory protective effect on inflammatory osteoblasts induced by lipopolysaccharide.