神经源性膀胱排尿报警装置的生物相容性研究

目的 研究神经源性膀胱排尿报警装置采用硅胶包埋永磁铁的生物相容性.方法 根据国家标准GB/T16886医疗器械生物学评价的要求对硅胶包埋的永磁铁进行细胞毒性实验、致敏实验、皮内刺激实验和急性全身毒性实验.采用琼脂扩散法计算永磁铁作用24 h后L929细胞的褪色指数和溶解指数,评价样品细胞毒性.使用样品浸提液对30只雄性豚鼠进行常规诱导和激发,24、48 h观察豚鼠腹侧皮肤的红斑水肿反应等级,评价样品的致敏性.观察2只雄性健康新西兰兔皮内注射浸提液后24、48及72 h局部组织的红斑水肿反应等级,评价样品的皮内刺激作用.观察10只雄性昆明种小鼠经尾静脉注射浸提液后4、24、48及72 h一般状态、毒性表现和死亡动物数,评价样品的急性毒性反应.将永磁铁固定在3条犬的膀胱前壁后2、4及8周,观察犬一般反应和局部病理变化.结果 硅胶包埋的永磁铁具有轻微细胞毒性作用,无致敏作用、皮内刺激作用和急性全身毒性作用.永磁铁植入后,犬耐受性好,精神、食欲及二便无明显异常,切口愈合良好,未发生感染.术后2、4周犬大网膜与膀胱壁在永磁铁周围发生粘连,8周犬下腹壁与膀胱壁在永磁铁周围发生粘连.永磁铁周围的纤维囊壁薄,其下方的膀胱壁增厚,膀胱黏膜面正常.镜下见膀胱壁各层均有不同程度充血和水肿,从浆膜层到黏膜层逐渐减轻.在浆膜层内可见大量的急慢性炎性细胞浸润,血管充血明显,肌层明显增厚,肌间可见少量炎性细胞浸润,血管轻度充血.结论 神经源性膀胱排尿报警装置所采用的永磁铁经硅胶包埋后具有良好的生物相容性,符合临床使用要求.

BIOCOMPATIBILITY OF MICTURITION ALERT DEVICE DEDICATED TO NEUROGENIC BLADDER

OBJECTIVE: To investigate the biocompatibility of silica gel embedded permanent magnets of the micturition alert device dedicated to neurogenic bladder. METHODS: According to the national standards of biological evaluation of medical equipment (GB/T 16886), Shanghai Biomaterial Research and Test Center was confided to evaluate the biocompatibility of silica gel embedded permanent magnets both in vitro and in vivo, including cytotoxicity test, sensitization test, primary skin irritant test and acute general toxicity test. The cytotoxicity test was performed according to the agar diffusion method. The L929 cell discoloration index and cell lysis index were counted at 24 hours after the action of the specimen. The sensitization test was performed according to the maximal dose method. The skin response was evaluated in 30 male albino guinea-pigs at 24 and 48 hours after the routine induction and provocation of leaching liquors of the specimen. The primary skin irritant test was evaluated in 2 male healthy New Zealand rabbits according to the local tissue response at 24, 48 and 72 hours after intradermal injection of leaching liquors of the specimen. The acute general toxicity test was evaluated in 10 male Kumming mice musculus albus according to animal condition at 4, 24, 48 and 72 hours after injection of leaching liquors of the specimen through the caudal vein. Both the general reaction of canines and the pathology of the local bladder walls were observed at 2, 4 and 8 weeks after a permanent magnet was fixed on the anterior wall of urinary bladder in three canines. RESULTS: No sensitization, no stimulation and no acute general toxicity were observed except slight cytotoxicity to silica gel embedded permanent magnets. After implantation of a permanent magnet, the canines showed excellent tolerance, which manifested as no abnormality in spirit, appetite, urine and stool, healed wounds and no infection. Adhesions occurred between the epiploon and the bladder wall around the permanent magnet in two canines at 2 and 4 weeks, and between the lower abdominal wall and the bladder wall around the permanent magnet in the other canine at 8 weeks. The local bladder wall below permanent magnet was thickened, the fibrous capsule around the permanent magnet was thin, but the bladder mucosa was normal. Inflammatory reaction such as congestion, edema and inflammatory cells lessened from the serosa layer to the mucosa layer microscopically. CONCLUSION: Silica gel embedded permanent magnets used in the micturition alert device dedicated to neurogenic bladder has excellent biocompatibility and meet the criteria for clinical application.