ABSTRACT
Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength.
Subject(s)
Humans , Alloys , Biomechanical Phenomena , Bone and Bones , Ceramics , Magnesium , Materials Testing , Porosity , Tissue ScaffoldsABSTRACT
AIM:To investigate the effect of flavone on ocular blood flow in rabbit eyes and the formation of choroidal neovascularization(CNV)in rat model of age-related macular degeneration(AMD).METHODS:In in vivo studies,colored microsphere technique was used to determine the ocular blood flow in ocular hypertensive rabbit eyes.The rat eyes were treated with 5g/L flavone eye drops 3 times a day for 1 week before and 4 weeks after laser-induced injury of Bruch's membrane.The development of CNV was determined by fluorescein angiography(FA)performed on weeks 2 and 4.In in vitro studies,the effect of flavone on the viability of HUVECs was measured by MTT assay.RESULTS:The ocular blood flow in rabbit eyes was significantly increased after flavone instillation.Flavone significantly inhibited the formation of laser induced CNV.In vitro resultsshowedthat fiavoneinhibited the proliferation of HUVECs.CONCLUSION:Flavone could increase ocular blood flow and inhibit the formation of CNV.
ABSTRACT
AIM: To study the effects of Tetramethylpyrazine (TMP) on retinal pigment epithelium (RPE) degeneration, choroidal blood flow and oxidative stress of RPE cells.METHODS: The 35mg/kg NaIO3-induced RPE degeneration rat eyes was given 25μg 1% TMP eye drops 3 times a day for 7 days before NaIO3 injection, and then 2 to 4 weeks after NaIO3 injection. RPE function was measured with c-wave of electroretinogram (ERG). Colored microsphere technique was used for in vivo experiments to determine the choroidal blood flow in ocular hypertensive (40mmHg) rabbit eyes. Methylthiazoltetrazolium (MTT) assay was used to study in vitro effect of TMP on various oxidants induced injury in the hRPE (ARPE-19 (ATCC, Manassas, VA, USA)) . RESULTS: Two weeks after NaIO3 injection, the amplitude of ERG c-wave fell markedly in NaIO3 group to 36% of control group (P<0.01). No apparent difference was observed in TMP+NaIO3 group. Four weeks later, the NaIO3 group fell to 46% of control group (P<0.01), while the TMP+NaIO3 group fell to only 77% of control group (P<0.01). There was a 67% reversal of the ERG c-wave by TMP as compared to NaIO3 group (P<0.01). The choroidal blood flow was significantly increased at all time points (at 30, 60 and 120 minutes after TMP instillation) as compared with corresponding controls. TMP had no effect on hypoxia-(1%O2), t-BHP- and H2O2-induced damage in RPE cells. 10μg/mL TMP could reverse 1 and 3mmol/L NaN3-induced loss of viability of RPE by 18.5% (P<0.01) and 23% (P<0.01), respectively. 30μg/mL TMP could reverse 30 and 100mmol/L NaIO3 induced loss of viability of RPE by 18.1% (P<0.05) and 16.8% (P<0.01), respectively.CONCLUSION: TMP can significantly protect RPE from NaIO3 induced degeneration in vivo and oxidative stress in vitro and can increase choroidal blood flow markedly in vivo .
ABSTRACT
AIM: To investigate the effect of flavone on oxidation-induced injury in retinal pigment epithelium(RPE) cells. METHODS: In in vivo studies, NaIO3-induced RPE degeneration in rat eyes were treated with 5g/L flavone eye drops 3 times a day for 1 week before and 4 weeks after NaIO3injection. At the end of 2 and 4 weeks, all rats were measured c-wave by electroretinogram(ERG). In in vitro studies,ARPE-19 cells were treated with hypoxia, H2O2, NaN3and t-BHP to induce cell damages. MTT assay was used to measure the viable cells. RESULTS: The ERG c-wave results showed that flavone reversed NaIO3-induced injury at the end of 4 weeks. In vitro results showed flavone reversed the various oxidants-induced injuries in RPE cells.CONCLUSION: Flavone could prevent the RPE from oxidation-induced injury both in vivo and in vitro.