年轻血液对小鼠脊髓损伤的影响

目的通过建立连体小鼠模型,研究年轻小鼠血液对小鼠脊髓损伤的影响。方法对12月龄C57BL/6小鼠实施脊髓损伤手术,并于损伤7 d后将脊髓损伤C57BL/6小鼠与年轻(3月龄)或同龄(12月龄)EGFP转基因小鼠连体配对。连体配对14 d后,通过脾脏细胞分离和荧光显微镜检测对小鼠连体模型进行血液嵌合检测。连体配对28 d后,对连体模型中的脊髓损伤C57BL/6小鼠进行BBB运动功能评分和HE染色。结果血液嵌合分析显示,脊髓损伤C57BL/6小鼠-EGFP转基因小鼠连体模型可形成稳定的血液嵌合。BBB评分显示,与年轻EGFP小鼠连体配对的脊髓损伤C57BL/6小鼠运动功能恢复情况显著优于与同龄EGFP小鼠连体配对者。与年轻EGFP小鼠连体配对的脊髓损伤C57BL/6小鼠脊髓组织空洞面积较与同龄EGFP小鼠连体配对者明显缩小。结论年轻血液可显著促进小鼠脊髓损伤恢复。     

醛糖还原酶在小鼠损伤脊髓小胶质/巨噬细胞中的表达及其作用

目的:观察小鼠在脊髓损伤(SCI)后,醛糖还原酶(AR)在脊髓损伤后修复过程中的作用及可能的机制。方法:采用C57BL/6-ar+/+(B6野生型小鼠)和C57BL/6-ar-/-(B6-AR基因敲除)小鼠,建立脊髓重度夹伤模型。首先分析了AR分子在损伤脊髓中的细胞表达类型及脊髓损伤后AR分子mRNA的表达水平变化情况;通过BBB运动学分析,比较AR基因敲除小鼠和野生型小鼠脊髓损伤后运动功能恢复情况,对比损伤区面积变化;通过qRT-PCR方法,检测对比M1/M2型巨噬细胞特异分子iNOS和Arg I的表达变化。结果:AR分子在野生型小鼠损伤脊髓中的小胶质/巨噬细胞中高表达;qRT-PCR研究发现:脊髓损伤后AR表达逐渐升高,在损伤后第3天达到高峰。AR敲除小鼠在脊髓损伤后,其运动功能恢复好于野生型小鼠(P<0.05),同时损伤区面积也小于对照组。AR基因缺失后,损伤脊髓中的小胶质/巨噬细胞通过高表达Arg I向M2型巨噬细胞方向极化。结论:AR通过调节脊髓中小胶质/巨噬细胞的极化来影响脊髓损伤后的修复。     

异基因MHC Ⅰ修饰对骨髓细胞的免疫学特性的影响

目的：观察异基因MHC Ⅰ修饰对骨镑细胞的免疫学特性的影响，探讨MHC Ⅰ类分子在诱导免疫耐受中的作用机制。方法：由逆转录病毒载体pMSCV介导，将BALB/C小鼠的MHC Ⅰ类分子H—2D^d基因导入C57BL/6小鼠的骨骼细胞，流式细胞仪检测转染后基因的表达。MTT法检测混合淋巴细胞反应，乳酸脱氢酶释放法测定BALB/C小鼠NK细胞对H-2D^d修饰后C57BL/6小鼠骨髓细胞的杀伤活性。结果：重组逆转录病毒感染的C57BL/6小鼠骨髓细胞对BALB/C小鼠脾细胞的刺激强度或应答程度，与未转染和空载体病毒感染的C57BL/6小鼠骨髓细胞相比都显著减弱。BALB/C小鼠NK细胞对转染H-2D^d基因后的C57BL/6小鼠骨髓细胞的杀伤显著降低。结论：在骨髓移植中用受者MHC Ⅰ分子修饰供者骨髓细胞可能诱导免疫耐受。     

C57BL/6小鼠胚胎成纤维细胞生物学特性及饲养层制备

背景：昆明小鼠胚胎成纤维细胞是目前最常用的饲养层细胞,C57BL/6小鼠胚胎成纤维细胞作为饲养层的研究鲜有报道。目的：体外分离和培养C57BL/6小鼠胚胎成纤维细胞,制备饲养层,力求扩大小鼠胚胎成纤维细胞的来源。方法：用不同浓度胰蛋白酶分步消化法体外分离和培养C57BL/6小鼠胚胎成纤维细胞,观察其生物学特性,研究其生长规律,并制备小鼠胚胎成纤维细胞饲养层,检测干细胞在所制备饲养层上的生长状态。结果与结论：不同浓度胰蛋白酶分步消化法制备的C57BL/6小鼠胚胎成纤维细胞生长状态好,获得的成纤维细胞数量多,增殖活跃。在细胞冻存后1,2周、1,3,6个月内复苏的细胞存活率差异无显著性意义。C57BL/6小鼠胚胎成纤维细胞在第2-5代增殖旺盛,第6代以后细胞增殖出现明显下降。种植到培养皿上的C57BL/6小鼠饲养层细胞在种植后3 d内活力高,种植4 d以后细胞活力急剧下降。所以C57BL/6小鼠胚胎成纤维细胞来源的饲养层的最佳使用时间为灭活后3 d内,C57BL/6小鼠胚胎成纤维细胞饲养层和昆明小鼠胚胎成纤维细胞饲养层一样,能很好地支持胚胎干细胞及诱导多能干细胞生长。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

移植器官体积对小鼠皮肤移植物生存时间影响的实验研究

目的 探讨移植器官体积对移植器官生存时间的影响.方法 C57BL/6小鼠与BALB/c小鼠杂交获得F1小鼠,1.5×107个F1小鼠脾脏细胞输注给新生C57BL/6小鼠;混合淋巴细胞反应检测体内同种异体反应性T细胞的克隆清除;Na(i)ve(初始)C57BL/6小鼠和新生期处理的C57BL/6小鼠移植F1小鼠皮肤,皮片大小分别为0.5 cm2和1 cm2,观察皮片的生存时间.结果 新生期C57BL/6小鼠输注F1小鼠脾脏细胞后体内同种异体反应性T细胞数量显著减少,对移植抗原的反应性减弱;Na(i)ve小鼠迅速排斥F1小鼠皮肤移植物,0.5 cm2和1 cm2组皮肤移植物的生存时间分别为(8.9±1.0)d和(9.3±1.0)d,两组间差异没有统计学意义(P＞0.05);新生期处理的C57BL/6小鼠移植F1小鼠皮肤,1 cm2组皮肤移植物生存时间为(63±28)d,大于0.5 cm2组皮肤移植物(28±16)d,两组间差异具有统计学意义(P＜0.05).0.5 cm2组皮肤移植物在60d内完全排斥,1 cm2组皮肤移植物在100 d时仍有部分存活,形成长期耐受.结论 降低移植受体排斥强度的同时增加移植器官的体积可延长移植器官的生存时间.     

荷EL4肿瘤小鼠模型的建立及美法仑抑瘤作用免疫机制的探讨

目的:建立荷小鼠淋巴瘤EL4的野生型C57BL/6小鼠及其裸鼠模型,探讨美法仑(melphalan)抑瘤作用的免疫机制。方法:给正常野生型C57BL/6小鼠皮下接种小鼠淋巴瘤EL4细胞,建立荷EL4肿瘤的小鼠模型。于野生型C57BL/6小鼠皮下接种瘤细胞后12d,经腹腔给荷瘤小鼠单次注射不同剂量的美法仑,找出美法仑可发挥最大的抑瘤作用,并能致使肿瘤消退、不再复发的最小使用剂量。然后再给野生型C57BL/6小鼠及其裸鼠(遗传背景相同)皮下同时接种小鼠淋巴瘤EL4细胞建立两种荷瘤小鼠模型。同样于接种瘤细胞后12d,经腹腔给两种荷瘤小鼠模型均注射可使野生型C57BL/6小鼠肿瘤消退、不再复发的最低剂量的美法仑,以正常野生型C57BL/6小鼠为对照,观察在T淋巴细胞缺陷的裸鼠体内美法仑的抑瘤作用。结果:注射7.5mg/kg美法仑治疗后,免疫功能正常的野生型C57BL/6荷瘤小鼠的肿瘤消退;而荷瘤C57BL/6裸鼠的肿瘤仍继续生长。结论:单一剂量的美法仑对荷淋巴瘤EL4小鼠具有明显的治疗作用,其作用的发挥需要T淋巴细胞的参与,可能与T细胞的杀伤作用有关。     

吗啡持续刺激对小鼠树突状细胞成熟的影响

为研究吗啡持续刺激对C57BL/6小鼠骨髓来源的树突状细胞成熟的影响.体外培养C57BL/6小鼠骨髓来源的树突状细胞,在培养过程中给予吗啡刺激,应用流式细胞术检测细胞表型CD11c、Ia、CD86的变化.吗啡干预各组树突状细胞中细胞表型CD11c、Ia、CD86表达较对照组显著升高.吗啡持续刺激能够促进小鼠树突状细胞的...     

原代小鼠小胶质细胞培养及尼古丁抑制肿瘤坏死因子α分泌的研究

目的 本研究通过摇床法分离纯化培养小鼠原代小胶质细胞,并研究尼古丁对小胶质细胞肿瘤坏死因子α（TNF-α ）的表达和分泌的影响。方法 从C57 BL/6新生鼠大脑中分离出皮层,切碎研磨后进行混合培养,摇床法分离纯化小胶质细胞并培养。CD11b、Iba1作为小胶质细胞特异性标记物用来检测、鉴定小胶质细胞,在激光共聚焦显微镜下观察、计数免疫荧光细胞化学染色后的阳性细胞。将纯化的小胶质细胞设置为三个组,分别为空白对照组,LPS组,LPS+NIC组。 LPS+NIC组先加入10 ug/ml LPS处理30 m     

化疗治愈荷瘤小鼠模型的建立及氟尿嘧啶抑瘤作用的免疫机制

目的:建立荷瘤野生型C57BL/6小鼠及C57BL/6裸鼠模型,探讨5-氟尿嘧啶(5-FU)抑瘤作用的免疫机制。方法:给正常野生型C57BL/6小鼠皮下接种小鼠淋巴瘤EL4细胞,建立荷EL4肿瘤的小鼠模型。接种瘤细胞后12d,荷瘤小鼠腹腔单次注射不同剂量的5-FU,找出5-FU可发挥最大的抑瘤作用、并能致使荷瘤小鼠肿瘤消退不再复发的最小使用剂量。遗传背景相同的野生型C57BL/6小鼠及C57BL/6裸鼠同时皮下接种小鼠淋巴瘤EL4细胞,建立两种荷瘤小鼠模型。接种瘤细胞后12d,两种荷瘤小鼠腹腔内同时注射可使野生型C57BL/6荷瘤小鼠肿瘤消退不再复发5-FU的最低剂量,以正常野生型C57BL/6小鼠为对照,观察5-FU对T淋巴细胞缺陷裸鼠的抑瘤作用。结果:以75mg/kg5-FU治疗1周后,两种荷瘤小鼠的肿瘤以相同的速率缩小直至消失。但在5-FU治疗2周后,T淋巴细胞缺陷的C57BL/6裸鼠肿瘤复发,而免疫功能正常的野生型C57BL/6小鼠肿瘤治愈。结论:单一剂量的5-FU对荷淋巴瘤EL4小鼠具有明显的近期治疗效果,5-FU抑瘤作用的发挥不需要T细胞参与;但5-FU抗肿瘤作用的远期疗效与机体T淋巴细胞功能密切相关。     

腺病毒转染法构建表达乙型肝炎病毒核心蛋白小鼠肝癌细胞系及其在乙肝疫苗评价中的应用

目的 构建一种可高效表达乙型肝炎病毒(Hepatitis B virus,HBV)核心蛋白(HBc)C57BL/6小鼠来源肝癌细胞系,并以其作为靶细胞评价乙肝基因疫苗在C57BL/6小鼠体内所引起的HBc特异性细胞毒性T细胞(CTL)的活性.方法 以HBV全基因组为模板,采用PCR方法扩增HBc基因,插入AdEasy腺病毒穿梭载体,构建携带HBc蛋白的腺病毒穿梭载体AD-HBc,电转携带有腺病毒骨架质粒(Ad-Easy)的E.coli BJ5183感受态细胞,获得重组腺病毒质粒AD-CMV-HBc,经PmeⅠ线性化处理后转染HEK293细胞进行包装得到相关的重组腺病毒,再感染C57BL/6小鼠来源肝癌细胞系Hepa1-6.结果 成功构建表达HBc蛋白的重组腺病毒,在体外对Hepa1-6细胞的感染率几乎为100％,并且HBc蛋白得到高效表达.以此为靶细胞用于pVAX1-HBc基因疫苗免疫C57BL/6小鼠产生的CTL活性的体外检测.结论 我们成功构建HBc蛋白表达的靶细胞系,对研究乙肝病毒核心抗原(HBcAg)所引起的细胞免疫反应及乙肝发病机理等方面有重要意义.     

Deficiency in inducible nitric oxide synthase protects mice from ozone-induced lung inflammation and tissue injury

Inhalation of ozone causes Type I epithelial cell necrosis and Type II cell hyperplasia and proliferation. This is associated with an accumulation of activated macrophages in the lower lung, which we have demonstrated contribute to tissue injury. Nitric oxide (NO) is a highly reactive cytotoxic macrophage-derived mediator that has been implicated in lung damage. In the present studies we used knockout mice with a targeted disruption of the gene for inducible nitric oxide synthase (NOSII) to analyze the role of NO in ozone-induced lung inflammation and tissue injury. Treatment of wild-type control mice with ozone (0.8 ppm) for 3 h resulted in a time-dependent increase in protein and cells in bronchoalveolar lavage fluid, which reached a maximum 24-48 h after exposure. Alveolar macrophages isolated from animals treated with ozone were found to produce increased amounts of NO, as well as peroxynitrite. This was correlated with induction of NOSII protein and nitrotyrosine staining of lung macrophages in tissue sections and in culture. Production of superoxide anion and prostaglandin (PG)E2 by alveolar macrophages was also increased after ozone inhalation. In contrast, alveolar macrophages from NOSII knockout mice did not produce reactive nitrogen intermediates even after ozone inhalation. Moreover, production of PGE2 was at control levels. NOSII knockout mice were also protected from ozone-induced inflammation and tissue injury, as measured by bronchoalveolar lavage protein and cell number. There was also no evidence of peroxynitrite-mediated lung damage in these animals. Taken together, these data demonstrate that NO, produced via NOSII, and potentially, its reactive oxidative product peroxynitrite, play a critical role in ozone-induced release of inflammatory mediators and in tissue injury.     

Pattern of infection and selective loss of Ia positive cells in suckling and adult mice inoculated with lactic dehydrogenase virus

Summary Lactic dehydrogenase virus (LDV) infected cells were localised in cryostat sections of infected adult and suckling mice by fluorescent antibody staining. In almost every organ except brain and spinal cord, LDV infected cells were present in interstitial connective tissue, including dermis and submucosa of gastrointestinal and urinogenital tracts. They were also present in liver sinusoids and red pulp of spleen. The tissue distribution, shape, and fluorescence staining pattern of infected cells were similar in adult and suckling mice. The reactivity with monoclonal antibody to mouse macrophages (F4/80) and to Ia antigens indicated that infected cells were Ia antigen positive macrophages, and this was confirmed in double labelling experiments. Peak numbers of LDV infected cells were seen in every organ 12–18 hours post infection (p.i.), disappearing rapidly thereafter until at 48 hours p.i. they could no longer be detected. At the same time Ia positive cells fell to undetectable levels, although macrophages were still present in reduced numbers. At 7 days p.i. the total number of macrophages in sections had returned to normal, but the number of Ia positive cells remained at low levels.Macrophages recovered from peritoneal cavity and spleen of intraperitoneally infected mice were also studied. Ia positive cells had virtually disappeared from peritoneal cavity at 24–48 hours, and from spleen at 24–72 hours. Three weeks after infection the proportion of Ia positive cells was still low when compared with that of normal mice suggesting selective loss of these cells.With 4 Figures     

跨膜型和分泌型肿瘤坏死因子α对内毒素性休克肝的影响及意义

目的：探讨分泌型（S）和跨膜型（TM）肿瘤坏死因子α（TNF－α）对内毒素性休克肝的影响及意义。方法：首先使用埃氏大肠杆菌死菌液制备大鼠内毒素性休克模型;并分不同时间点检测血清中的S－TNF－α、腹腔巨噬细胞表面上的TM－TN－α;然后,在给大鼠注射死菌液之前30min,注射TNF－α转化酶（TACE）反义寡核苷酸（5mg/kg);6h后分别检测S－TNF－α、TN－TNF－α水平;检查肝脏的病理改变,并监测各组大鼠的血压变化。结果：在内毒素性休克过程中,TM－TNF－α表达的动态变化不同于S－TNF－α,TM－TNF－α在注射菌液30min后开始升高,4．5h达最高峰,随后有所下降,但一直维持在较高水平。TACE反义寡核苷酸有能有效地抑制TM－TNF－α转化为S－TNF－α,使腹腔巨噬细胞表面上的TM－TNF－α表达明显增高（P＜0．001）,使血压维持在正常水平,肝脏未见病理改变。结论：内毒素性休克的病理过程主要与S－TNF－α有关,而TM－TNF－α则可抵抗内毒素的攻击,稳定血压,限制炎症反应及保护肝组织免受损伤,此研究为临床治疗休克和感染性疾病提供了新的线索和实验依据。     

Focal cerebral ischemia/reperfusion injury in mice induces hematopoietic prostaglandin D synthase in microglia and macrophages

Hematopoietic prostaglandin D synthase is a key enzyme in synthesis of prostaglandin D. Hematopoietic prostaglandin D synthase is expressed in microglia of the developing mouse brain. This study determined the serial changes and cellular localization of hematopoietic prostaglandin D synthase, and its role in cerebral ischemia/reperfusion injury using C57BL/6 mice (n=84) and bone marrow chimera mice (n=16). The latter mice were selected based on their expression of enhanced green fluorescent protein in bone marrow/blood-derived monocytes/macrophages. The middle cerebral artery was occluded for 60 min, followed by reperfusion. Hematopoietic prostaglandin D synthase expression was examined by immunohistochemistry and Western blotting. Hematopoietic prostaglandin D synthase-positive cells were mainly expressed in the peri-ischemic area at 12 h (P<0.05) and 24 h (P<0.001) after reperfusion, while they were mostly found in the transition area at 48-72 h postreperfusion (P<0.001). There was a significant increase in staining intensity as well as number of hematopoietic prostaglandin D synthase-positive cells in the ischemic core at 5-7 (P<0.001) days postreperfusion. Hematopoietic prostaglandin D synthase-positive cells also co-expressed ionized calcium-binding adapter molecule 1, a marker of microglia/macrophages, and cyclooxygenase-2, but not markers of neurons, oligodendrocytes and astrocytes. Until 72 h postreperfusion, many enhanced green fluorescent protein-positive cells were negative for hematopoietic prostaglandin D synthase, but the number of hematopoietic prostaglandin D synthase-enhanced green fluorescent protein coexpressing cells increased significantly at 5-7 days after reperfusion. Our results indicate that hematopoietic prostaglandin D synthase is mainly produced by endogenous microglia until 72 h after reperfusion, but at 7 days after reperfusion, it is also produced by migrating bone marrow/blood-derived macrophages in the ischemic brain tissue. We speculate that hematopoietic prostaglandin D synthase in the brain has different functions during early and late phases of ischemia.     

金属氧化物材料对小鼠急性肺损伤作用的研究

 摘要：目的 以C57 BL/6小鼠为模型对氧化铜、氧化铁、氧化钛、氧化硅等金属氧化物纳米材料的呼吸系统毒性进行比较和评估。方法 给C57 BL/6小鼠气管注射金属氧化物纳米材料,对给药后小鼠的死亡率、肺湿干比以及小鼠肺泡灌洗液中细胞因子的水平进行检测。结果 注射较高剂量氧化铜纳米材料的小鼠在24 h 内全部死亡,而相同剂量下注射其他金属氧化物未导致小鼠死亡;注射氧化铜纳米的小鼠肺湿干比显著高于对照组,且小鼠肺泡灌洗液中白细胞介素6的水平显著上升,而其他金属氧化物并未导致小鼠肺湿干比或白细胞介素6的水平的显著升高。结论 氧化铜纳米材料对C57 BL/6小鼠具有很强的致死性,并且引起小鼠肺水肿,导致小鼠急性肺损伤。而其他几种金属氧化物纳米材料的毒性较低,对小鼠的急性肺损伤作用较小。炎症因子IL-6水平在注射氧化铜纳米后显著增加,可能在氧化铜诱导的急性肺损伤中起到重要作用。     

Role of tumor necrosis factor-alpha in the spontaneous development of pulmonary fibrosis in viable motheaten mutant mice.

The viable motheaten mutant mouse is severely immunodeficient and dies from a naturally occurring progressive pulmonary inflammation at approximately 10 weeks of age. The pulmonary disease is characterized by excessive macrophage accumulation in the lung and fibrosis. We correlated the development of lung injury in viable motheaten mice with tumor necrosis factor-alpha (TNF-alpha) levels in serum and lung. Significantly increased serum TNF-alpha levels were observed by enzyme-linked immunosorbent assay in viable motheaten mice at 4, 6, and 10 weeks of age as compared with normal control littermate mice. These ages correlated well with observed changes in lung wet weights, lung collagen content, and histological evidence of pulmonary inflammation and fibrosis. Qualitative assessment of lung tissue TNF-alpha levels was performed by immunohistochemical staining using immunoperoxidase techniques. These studies revealed increased levels of TNF-alpha in macrophage-like cells in viable motheaten mice from 5 to 10 weeks of age as compared with littermate control animals. Alveolar macrophages isolated from viable motheaten mice produced significantly greater amounts of TNF-alpha when stimulated with lipopolysaccharide compared with alveolar macrophages from control animals. In addition, administration of anti-TNF-alpha antibody to motheaten bone marrow recipient mice decreased the severity of acute lung injury. The results demonstrate a close correlation between the development of pulmonary injury and TNF-alpha levels in this model of spontaneously developing fibrotic lung disease.     

Possible involvement of the M2 anti-inflammatory macrophage phenotype in growth of human gliomas

Within tumours, many non-neoplastic cells such as fibroblasts, endothelial cells, and macrophages assist tumour growth by producing various growth factors and pro-angiogenic cytokines. Various tumour-derived molecules drive tumour-associated macrophages towards an anti-inflammatory phenotype (M2) and thus promoting tumour growth. Here we investigated microglia/macrophage differentiation in glioma tissues by means of immunostaining of paraffin-embedded glioma samples. The number of microglia/macrophages with positive staining for CD163 and CD204, which are believed to be markers for M2 macrophages, was correlated with the histological grade of the gliomas. The ratio of M2 macrophages in the tumour-associated microglia/macrophages was also associated with the histological grade. Culture supernatant from the glioma cell line can stimulate macrophages to develop into the M2 phenotype in vitro. Macrophage colony-stimulating factor (M-CSF), which strongly induces M2 polarization of macrophages, was significantly correlated with histological malignancy and with the proportion of M2 microglia/macrophages in vivo. In addition, the proportion of M2 microglia/macrophages and M-CSF expression in tumour cells correlated well with proliferation of glioblastoma cells. These results suggest that tumour-derived M-CSF induces a shift of microglia/macrophages towards the M2 phenotype, which influences tumour growth. Evaluation of the proportion of M2 microglia/macrophages and M-CSF expression in tumour tissue would be useful for assessment of microglia/macrophage proliferative activity and the prognosis of patients with gliomas.     

Nuclear retention of IL‐1α by necrotic cells: A mechanism to dampen sterile inflammation

Sterile inflammation is a host response to tissue injury that is mediated by damage‐associated molecular patterns released from dead cells. Sterile inflammation worsens damage in a number of injury paradigms. The pro‐inflammatory cytokine IL‐1α is reported to be a damage‐associated molecular pattern released from dead cells, and it is known to exacerbate brain injury caused by stroke. In the brain, IL‐1α is produced by microglia, the resident brain macrophages. We found that IL‐1α is actively trafficked to the nuclei of microglia, and hence tested the hypothesis that trafficking of IL‐1α to the nucleus would inhibit its release following necrotic cell death, limiting sterile inflammation. Microglia subjected to oxygen‐glucose deprivation died via necrosis. Under these conditions, microglia expressing nuclear IL‐1α released significantly less IL‐1α than microglia with predominantly cytosolic IL‐1α. The remaining IL‐1α was immobilized in the nuclei of the dead cells. Thus, nuclear retention of IL‐1α may serve to limit inflammation following cell death.     

Cell viability and inflammatory response in hydrogel sponges implanted in the rabbit cornea

In the quest for the development of a functional keratoprosthesis, the biocompatibility of the porous skirt material in the Chirila keratoprosthesis (KPro) was investigated. The population of live and dead cells within, and the inflammatory response to, a tissue-integrating poly(2-hydroxyethyl methacrylate) (PHEMA) sponge were studied. Samples of the hydrogel sponge were implanted in rabbit corneas and explanted at predetermined time points up to 12 weeks. The explanted sponges were subjected to cell viability assay using two types of fluoroprobes, 5-chloromethylfluorescein diacetate and ethidium homodimer-1. A semiquantitative analysis was performed to assess the number of dead cells within the sponge and in the area of corneal stroma proximal to the sponge. Five rabbits were used for each end point (2, 4 and 12 weeks). To investigate the inflammatory response to the sponge, immunocytochemistry, using specific antibodies to rabbit macrophages, enzyme histochemistry of chloroacetate esterase (to detect neutrophils) and transmission electron microscopy (TEM) were also employed at 24 h, 2, 4 and 12 weeks after implantation. Four weeks after implantation, fewer viable cells were observed in the sponge when compared to the 2-week implant. However, the proportion of viable cells increased dramatically by 12 weeks. The proportion of nonviable cells decreased gradually with time; central sponge contained 34±11% dead cells after 2 weeks, and 15±4.3% after 12 weeks. The staining of inflammatory cells demonstrated the presence of macrophages and neutrophils up to 12 weeks after implantation. TEM confirmed the presence of these cell types and others, including eosinophils and myofibroblasts, as well as blood capillaries. The presence of a significant number of viable cells at each time point and the uniform reduction of the nonviable cell proportion with time suggests that the sponge is a conducive environment supporting a prolific, viable cellular colonization. Dead cells observed in the first instance indicate a normal injury pattern. However, the presence of a small but significant proportion of invading inflammatory cells 12 weeks after implantation confirms a characteristic pattern of wound healing within the sponges.