Résumé
Objective: To study the pharmacokinetics (PK) and tissue distribution of orientin in rabbits. Methods: The high-performance liquid chromatography method was developed and validated for the determination of orientin in rabbit plasma and tissues. The PK characteristics of orientin in rabbits were compared by three kinds of administration, iv, im, and ip injection, using 3P97 pharmacokinetic software to examine the PK parameters. Results: The elimination half-life (t1/2β) of three kinds of administration was higher than the distribution half-life (t1/2α). The PK of orientin eliminating in rabbit fitted the two compartment model. Orientin was mainly eliminated in rabbit. The distribution of orientin in tissue after iv injection was investigated, and the order of orientin AUC in each group was kidney > liver > lung > spleen > heart > brain. Conclusion: Orientin is distributed extensively in tissues such as kidney, liver, and lung. It is difficult for orientin to cross the blood brain barrier. © 2013 Tianjin Press of Chinese Herbal Medicines.
Résumé
It was recently discovered that a subset of osteoblasts functions as a key component of the hematopoietic stem cells (HSC) niche in vivo, controlling HSC self-renewal and multi-lineage differentiation. Disruption of Smad4 gene specifically in osteoblasts leads to a remarkable decrease of osteoblast number and endosteal surface area. In order to elucidate if the osteoblast loss has any effect on hematopoietic activity, the bone marrow (BM) and extramedullary hematopoiesis in the osteoblast-specific Smad4 knockout mice were systematically analyzed, the proportions of mature hematocytes in BM, liver and spleen were detected by flow cytometry, the hematopoietic progenitor number in different stages was measured by colong-forming assay, CFU-S and analysis of LSK cells. The results indicated that the conditional mutant mice demonstrated normal BM hematopoiesis without sign of extramedullary hematopoiesis. Furthermore, the proportion of hematopoietic progenitor cells was normal, while cell number/body weight of the conditional knockout mice increased. It is concluded that hematopoiesis is normally maintained in osteoblast-specific Smad4 knockout mice, and osteoblast loss does not of necessity result in the decrease in BM hematopoiesis.