摘要
<p><b>OBJECTIVE</b>To investigate the role of tumor necrosis factor (TNF) alpha on the homing efficiency of hematopoietic stem/progenitor cells (HS/PC) into bone marrow and its mechanism.</p><p><b>METHODS</b>CFSE-labeled umbilical cord blood (UCB) CD34+ cells were transplanted into irradiated (control group) or combined with TNF alpha prepared (experimental group) BALB/c recipient mice. The distribution in peripheral blood, liver, lung and homing characteristics in bone marrow and spleen of UCB CD34+ cells, in BALB/c recipient mice were determined 20 hours after xenotransplantation by flow cytometry (FACS) and their homing efficiency was calculated. ELISA was used to measure serum SDF-1 alpha level. CXCR4 expression levels of on UCB CD34+ cells were assessed by FACS pre-/post-manipulation with TNF alpha. SDF-1 alpha expression level in bone marrow and spleen was tested by immunohistochemistry.</p><p><b>RESULTS</b>UCB CD34+ cells mainly home into recipient mice bone marrow and spleen; The homing efficiency in experimental group bone marrow [(0.65 +/- 0.13)%] was significantly higher than that in control ones [(0.30 +/- 0.09)%, P < 0.01], whereas the homing efficiency in experimental group spleen was dramatically lower than that in control ones (P < 0.01); Treatment with TNF alpha did not affect recipient serum SDF-1 alpha level; After 18 hours co-cultured with TNF alpha, the CXCR4e expression level on UCB CD34+ cells was similar to that on fresh ones; TNF alpha treatment induced significantly higher SDF-1 alpha expression on osteoblastic and stromal cells in bone marrow, and reversed spleen SDF-1 alpha gradient that was originally favorable for CD34+ cells homing.</p><p><b>CONCLUSION</b>TNF alpha enhances the homing efficiency of HS/PC via up-regulating SDF-1 alpha gradient in bone marrow, and might be an useful enhancer for HS/PC homing in clinical practice.</p>
Subject(s)
Animals , Female , Humans , Mice , Antigens, CD34 , Bone Marrow , Cell Movement , Cell Separation , Chemokine CXCL12 , Metabolism , Fetal Blood , Cell Biology , Hematopoietic Stem Cell Transplantation , Hematopoietic Stem Cells , Allergy and Immunology , Metabolism , Mice, Inbred BALB C , Receptors, CXCR4 , Metabolism , Transplantation Conditioning , Transplantation, Heterologous , Tumor Necrosis Factor-alpha , Pharmacology摘要
Objective To explore the regulation of berberine on the expressions of CDK4 and cyclin D1 in the neurons after the focal cerebral ischemia/reperfusion and the potential protective mechanism of berberine to neurons. Methods Fifty male Wistar rats were randomly divided into berberine-treated group (n=15), normal control group (n=5), sham-operated group (n=15) and vehicle-treated group (n=15). The model of focal cerebral ischemia was constructed using middle cerebral artery occlusion (MCAO) method. At 1, 3, 5 d after 1 hour ofischemia, the expressions and distributions of Bcl-2, cyclin D1 and CDK4 in each group were detected by immunohistochemistry, and morphological changes of brain were observed by HE staining. Results HE staining showed that in the berberine-treated group, the number of neurons was decreased less than that in vehicle-treated group at reperfusion 3 and 5 d. For the result of immunohistochemistry for Bcl-2 positive neurons, there was no obvious difference between berberine-treated group and vehicle-treated group at reperfusion 1 d (P>0.05),however, the number of the Bcl-2 positive cells in berberine-treated group at reperfusion 3 and 5 was significantly increased (P<0.01), and the numbers of cyclin D 1 and CDK4 positive cells were decreased as compared with those in the vehicle-treated group. Conclusions In the rat focal ischemia model,berberine can inhibit the neural expressions of cyclin D1 and CDK4 in the penumbra, that indicates berberine may have the potential of neural protection. The possible mechanism is that berberine can decrease the neural expression ofcyclin D1 and prevent it from entering the nucleus, thereby blocking the cascade reaction and suppressing the apoptosis mediated by cyclin D1.
摘要
The novel paclitaxel-loaded nanopaticle through surface modification with didodecylmethylammonium bromide (DMAB) was prepared and its prevenative against neointimal formation in a rabbit carotid artery injury model was tested. Paclitaxel-loaded nanoparticles were prepared from oil-water emulsions using biodegradable poly (lactic acid-co-glycolic acid) (PLGA). Specific additive for surface conjugation was added after particle formation. To enhance arterial retention using a cationic surfactant, DMAB, was used. The size and distribution, surface morphology and surface charge of the paclitaxel-loaded nanoparticles were then investigated by laser light scattering, scanning electron microscope and zeta potential analyzer. The drug encapsulation efficiency (EE) and in vitro release profile were measured by high-performance liquid chromatography (HPLC). Balloon injured rabbit carotid arteries were treated with single infusion of the paclitaxel-loaded NP suspension and observed for 28 days. The inhibitory effects of vascular smooth muscle cell migration and proliferation were evaluated as end-point. The NPs showed spherical shape with diameter ranging from 200 to 500 nm. The negatively charged PLGA NPs shifted to positive after the DMAB modification. The in vitro drug release profile showed a triphasic release pattern. 28 days later, morphologic analysis revealed that the inhibitory effect of intima proliferation is dose-dependent, and the 30 mg x mL(-1) nanoparticle concentration suspension could completely inhibit proliferation of intima. Paclitaxel-loaded nanoparticles through surface modification with DMAB provide an effective means of inhibiting proliferation response to vascular injury in the rabbit.