Preparation and evaluation of blank and doxorubicin loaded poly (acrylic acid) microspheres for embolization / 北京大学学报(医学版)

OBJECTIVE@#To prepare ion exchange doxorubicin-loaded poly (acrylic acid) microspheres (DPMs) and evaluate the properties of these chemoembolic agents.@*METHODS@#Poly (acrylic acid) microspheres (PMs) without drug were prepared by inverse suspension polymerization method and then doxorubicin was loaded by ion exchange mechanism to prepare DPMs. Optical microscope was used to investigate the morphology and particle size distribution of PMs and DPMs; fluorescence microscope and confocal microscope were used to observe the distribution of doxorubicin after drug loading. Elasticities of both the microspheres were evaluated by texture analyzer. High performance liquid chromatography (HPLC) method was established to determine the drug loading behavior of PMs and releasing behavior of DPMs. The in vivo embolic property was evaluated by embolizing the hepatic artery of a rabbit with 0.1 mL of DPMs.@*RESULTS@#PMs and DPMs were both spherical in shape, smooth in surface and dispersed well. Doxorubicin was mainly in the outer area inside of DPMs and distributed evenly. The average particle size of PMs and DPMs were (283±136) μm and (248±149) μm, respectively. PMs and DPMs both had good compression ability with the Young's modulus of (62.63±1.65) kPa and (93.94±1.10) kPa separately. PMs reached the drug loading balance at 12 h, and the entrapment efficiency was greater than 99%. Drug loading of PMs in doxorubicin solution at the concentration of 5.0 g/L and 12.5 g/L was (19.78±0.27) g/L and (49.45±0.37) g/L, respectively. Doxorubicin released slowly from DPMs in PBS and the accumulative release percentages of DPMs with corresponding drug loading were 6.82%±0.02% and 2.83%±0.10% after 24 h, respectively. Arterial angiograms showed that the hepatic artery of the rabbit was successfully embolized with DPMs.@*CONCLUSION@#DPMs with good performance of loading doxorubicin could be a potential embolic agent for transcatheter arterial chemoembolization.

Effects of overdosed fluoride on rat's incisor expression of matrixmetalloproteinase-20 and tissue inhibitors of metalloproteinase-2 / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of overdosed fluoride on the expression of MMP-20 and TIMP-2 in rat incisor.</p><p><b>METHODS</b>20 Wistar rats were randomly divided into experiment group and control group. The distilled water was given in control group. 100 mg/L fluoride- was given in experiment group. After 8 weeks treatment, the rats were killed. Immunohistochemical staining was used to observe the expression of MMP-20 and TIMP-2 in rat incisors.</p><p><b>RESULTS</b>Immunohistochemical results demonstrated the presence of MMP-20 and TIMP-2 protein in ameloblasts, odontoblasts, stratum intermedium and the stellate reticulum of rat incisor. The imagination analysis results showed that the expression of MMP-20 was reduesed in experiment group (P<0.01), and the expression of TIMP-2 had no significant difference (P>0.05).</p><p><b>CONCLUSION</b>The overdosed fluoride inhibits the secretion of MMP-20 and leads to the disturbed balance between MMP-20, TIMP-2 in rat incisor, which leads to the delay of the amelogenin removal and the enamel demineralization.</p>

Effect of overdose fluoride on the expression of enamelin in rat mandibular incisor / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the effect of overdose fluoride on the expression of enamelin in rat mandibular incisor.</p><p><b>METHODS</b>Twenty Wistar rats were divided randomly into two groups. Animals were maintained in standard environment with free access to food and distilled water (control group) or water added with 100 mg/L F-(experimental group). The rats were killed in the eighth week. HE staining was used to observe the morphology of ameloblasts. Immunohistochemical staining was adopted to study the expressions of enamelin in rat incisor.</p><p><b>RESULTS</b>The ameloblasts of the treated rat were arranged in multi-layer. The ameloblasts in group II were thinner than those in group I. The structure of enamel matrix was in disorder. The expressions of enamelin in ameloblasts and odontoblasts were obviously inhibited in group II (P < 0.01).</p><p><b>CONCLUSION</b>The overdose fluoride inhibits the secretion of enamelin and leads to the abnormal development of enamel matrix.</p>