ABSTRACT
Objective To investigate the function of cAMP response element binding protein (CREB) and extracellular signal-regulated kinase (ERK1/2) in osteoclast differentiation mediated by Ca2+/calmodulin-dependent kinase Ⅱ (CaMK Ⅱ)δ,and elucidate the molecular mechanism thereof.Methods CaMK Ⅱδ RNA interference lentivirus vector was constructed and mouse RAW264.7 cells were transfected with the virus to determine the interference efficiency.After virus transfection,RAW264.7 cells were treated with 50ng/ml receptor activator of nuclear factor κB ligand (RANKL) and the phosphorylation levels of CREB and ERK1/2 were detected at different time points.The cells were also treated with PD98059,an ERK1/2 inhibitor,to determine the effect of ERK1/2 signal blocking on the expression of nuclear factor activated T-cells cytoplasmic 1 (NFATc1) and osteoclast differentiation.Results Interference efficiency of recombinant CaMK Ⅱδ virus vector was 77.2％ at mRNA level and 70.2％ at protein level.CaMK Ⅱδ RNA interference significantly suppressed phosphorylation of CREB and ERK1/2,and the levels ofp-CREB and p-ERK1/2 were down-regulated by 21％-55％ and 55％-64％,respectively.ERK1/2 inhibitor significantly down-regulated the protein expression of NFATc1,and the number of osteoclast,the number and size of bone resorption lacunae decreased by 39.3％,50.0％ and 52.3％,respectively.Conclusion CaMK Ⅱδ RNA interference may significantly suppress the phosphorylation of CREB and ERK1/2,and CREB and ERK1/2 have mediated the CaMK Ⅱδ-induced osteoclast differentiation.
ABSTRACT
OBJECTIVE: To investigate the pharmacokinetics of matrine injection by different routes of administration. METHODS: Twenty healthy SD rats were enrolled in this study. They were randomly divided into two groups and received intraperitoneal and intravenous administration of matrine injection at dose of 15 mg·kg-1 respectively. Blood samples (0.3-0.4 mL) were immediately collected into heparinized tubes before injection and at 0.033, 0.083, 0.167, 0.333, 0.5, 0.75, 1, 2, 3, 4, 6, 8, 12 h after injection. Plasma sample concentrations were determined by a validated LC-MS/MS method. The pharmacokinetic parameters including AUC0-12, AUC0-∞, MRT0-12, MRT0-∞, t½, Vd, CL and ρmax were calculated. RESULTS: The main pharmacokinetic parameters for matrine after intraperitoneal and intravenous administration at dose of 15 mg·kg-1 were as follows:AUC0-12 (10 166±2 426), (12 217±2 968) ng·mL-1·h;AUC0-∞ (10 230±2 432), (12 300±3 031)- ng·mL-1·h;MRT0-12 (1.91±0.41), (2.14±0.54) h;MRT0-∞ (2.01±0.41), (2.26±0.64) h; t½(2.26±0.89), (2.60±1.25) h;Vd(4 998±2 010), (6 175±2 540) mL;CL (1 531±315.0), (1 727±475.6) mL·h-1·kg-1; ρmax (5 246±1 187), (8 503±1 101) ng·mL-1, respectively. The bioavailability of intraperitoneal administration is 83.21%. CONCLUSION: No significant differences were observed in AUC, MRT, t½ and CL values of matrine between different administrations except for ρmax and Vd.