Biological Transport Of Nifedipine And Captopril By Osteoblasts From Adult Rat's Mandible

There are lots of side-effects during systemic use of anti-hypertension medicines. To select appropriate dosage form and administration route is necessary for patients and doctors to diminish the side-effect and to achieve treatment effect. Recently, Liu have proposed two new kinds of local administration routes, which is delivering medicine to the periodontium and the whole body through a special dental implant or the root canal. But little is known of the delivery process of medicines to oral tissues, especially the periodontal tissue and the alveolar bone. What's more, we know nothing about whether osteoblasts can take up anti-hypertension medicines. So we carried out experiments to study the biological transport of Nifedipine and Captopril by osteoblasts, to verify the hypothesis on delivering medicine to the whole body through a special dental implant system. This study was consisted of two parts:Part 1: primary culture and identif of osteoblastsObjective To investigate an efficient method of primary mandibular osteoblasts culture, and establish a foundation for further experimental study. Methods The mandible harvested from 4-6 weeks SD rats was stripped off all soft tissues including the periosteum, rinsed and cut to trivial bone block under sterile condition. Then, the bone block was subcultured in culture flask after digested with modified enzymatic digestion-explants method, the acquired cells were identified with invert microscope, alkaline phosphorase stain, immunohistochemistry stain of osteocalcin and stain of calcified nodules. Results The cells obtained from rat's alveolar bone were identified to be osteoblasts by invert microscope, alkaline phosphorase stain, immunohistochemistry stain of osteocalcin and stain of calcified nodule. Conclusion The modified enzymatic digestion-explants method is an ideal method to obtain and culture mandibular osteoblasts having typical characteristics.Part 2: biological transport of Nifedipine and Captopril by osteoblasts from adult rat's mandibleObjective: To investigate biological transport of Nifedipine and Captopril by osteoblasts from adult rat's mandible and to study the effect on biological transport by medicine concentration and incubation time, to verify the hypothesis on delivering medicine to the periodontium and whole body through a special dental implant system.Methods: Osteoblasts and MC3T3-E1 cells were incubated in Nifedipine and Captopril PBS solutions for 1, 3, 5, 10, 15, 20min. The intracellular antibiotics contents were measured by high performance liquid chromatography (HPLC) and the cell total protein was measured by Bradford protein assay. According to intracellular antibiotics and cell protein quality, the intracellular antibiotics contents are expressed in ng drug/μg protein. Results: 1. Nifedipine could be transported by both kinds of cells. The intracellular contents of osteoblasts were significantly higher than that of MC3T3-E1 cells (P<0.01) . The intracellular contents were dependent on the extracellular concentration. The intracellular contents of osteoblasts and MC3T3-E1 cells increased steadily with incubation time. 2. The intracellular Captopril of both kinds of cells couldn't be detected during the total observation time. Conclusion: Selection and differences are observed in transportation of Nifedipine and Captopril by osteoblasts and MC3T3-E1 cells, which demonstrate the possibility of delivering medicine to the periodontium and the whole body through a special dental implant system.In summary, the osteoblasts from adult rat's mandible were primarily cultured successfully and passaged stably by tissue explant and enzyme. The osteoblasts had the appropriate morphological characteristic and bilological properties. The results shows that Nifedipine could be transported by osteoblasts and MC3T3-E1 cells. The extracellular concentration and incubation time have effect on the intracellular content, which demonstrate the possibility of delivering medicine to the periodontium and the whole body through a special dental implant system. Captopril couldn't be transported by osteoblasts and MC3T3-E1 cells.