Chellat F, Tabrizian M, Dumitriu S, Chornet E, Magny P, Rivard C H, Yahia L
Biomedical Engineering Institute, Biomechanics and Biomaterials Research Group, Ecole Polytechnique, P.O. Box 6079, Station Down Town, Montreal, Quebec, H3C 3A7, Canada.
J Biomed Mater Res. 2000 Jul;51(1):107-16. doi: 10.1002/(sici)1097-4636(200007)51:1<107::aid-jbm14>3.0.co;2-f.
A novel hydrogel, CHITOXAN(TM) (CH-X), has potential as a vehicle for controlled drug delivery. The hydrogel is obtained by complexation of two polysaccharides, chitosan and xanthan. In the present work we investigated the biocompatibility of the complex using in vitro and in vivo models. The cytotoxic effects of CH-X microspheres as well as their degradation products at different concentrations were assessed on fibroblasts (fibroblast cell line L-929) using 3-(4,5-dimethylthiazole-2yl)-2,5-triphenyl tetrazolium) (MTT). The test is based on mitochondrial dehydrogenase cell activity as an indicator of cell viability. Interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) cytokines as well as nitric oxide (NO) production by macrophages (macrophage cell line J-774) were examined as indicators of cell activation. In vivo biocompatibility assessment was performed for 1 to 12 weeks. This study was performed using tablets obtained after compression of CH-X particles implanted at the subcutaneous level in male Wistar rats. CH-X biocompatibility and degradation were investigated using histological studies. Light and transmission electron microscopy (TEM) analyses were used to determine the foreign-body reaction and phagocytosis of the implants by macrophages. Fibroblast exposition to CH-X particles and degradation products did not show cytotoxic effects as measured by MTT test. TNF-alpha production was dependent on CH-X particles concentration, whereas IL-1beta production was found to be dose independent. CH-X extract products stimulated TNF-alpha secretion when used at the highest concentration (10 mg/mL), notably after 28 days' degradation time. No effect was observed on IL-1beta production when CH-X extracts were used in comparison to the control. The effects of CH-X particles on NO secretion were similar as on TNF-alpha. Histological studies showed that CH-X tablets broke down into particles which progressively degraded into smaller fragments. A significant fraction of the fragments was ingested by the macrophages after 12 weeks of implantation. Light microscopy studies showed a weak foreign-body reaction as a function of time and the fibrous layer thickness decreased with time of implantation.
一种新型水凝胶CHITOXAN™（CH-X）具有作为可控药物递送载体的潜力。该水凝胶通过壳聚糖和黄原胶这两种多糖的络合作用获得。在本研究中，我们使用体外和体内模型研究了该络合物的生物相容性。使用3-(4,5-二甲基噻唑-2-基)-2,5-三苯基四氮唑（MTT）评估了不同浓度的CH-X微球及其降解产物对成纤维细胞（成纤维细胞系L-929）的细胞毒性作用。该测试基于线粒体脱氢酶细胞活性作为细胞活力的指标。检测了巨噬细胞（巨噬细胞系J-774）产生的白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）细胞因子以及一氧化氮（NO），作为细胞活化的指标。进行了为期1至12周的体内生物相容性评估。本研究使用了将CH-X颗粒植入雄性Wistar大鼠皮下水平后压制而成的片剂。通过组织学研究对CH-X的生物相容性和降解情况进行了研究。使用光学显微镜和透射电子显微镜（TEM）分析来确定巨噬细胞对植入物的异物反应和吞噬作用。通过MTT试验测定，成纤维细胞暴露于CH-X颗粒和降解产物未显示出细胞毒性作用。TNF-α的产生取决于CH-X颗粒的浓度，而IL-1β的产生与剂量无关。当以最高浓度（10 mg/mL）使用时，CH-X提取物在降解28天后显著刺激了TNF-α的分泌。与对照组相比，使用CH-X提取物时未观察到对IL-1β产生的影响。CH-X颗粒对NO分泌的影响与对TNF-α的影响相似。组织学研究表明，CH-X片剂分解成颗粒，这些颗粒逐渐降解成更小的碎片。植入12周后，很大一部分碎片被巨噬细胞吞噬。光学显微镜研究显示，随着时间的推移，异物反应较弱，纤维层厚度随植入时间的延长而减小。
