腺病毒介导CDglyTK双自杀基因系统对裸鼠皮下移植瘢痕疙瘩的治疗作用

目的 探讨由大肠杆菌胞嘧啶脱氨酶(CD)基因/5-氟胞嘧啶(5-Fc)和单纯疱疹病毒胸苷激酶(HSV-TK)基因/丙氧鸟苷(GCV)基因治疗系统整合形成的腺病毒介导CDgly/TK双自杀基因系统对瘢痕疙瘩的治疗作用及其机制.方法 采用皮下移植保留表皮的入瘢痕疙瘩组织块的方法建立瘢痕疙瘩裸鼠模型,术后第7天将20只模型裸鼠分4组,每组5只.A组瘢痕内注射生理盐水;B组瘢痕内注射生理盐水+腹腔注射5-Fc和GCV;C组瘢痕内注射自行构建的莆组CDglyTK双自杀基因腺病毒(CDgly/TK);D组瘢痕内注射CDgly/TK+腹腔注射5-Fc和GCV;用药持续18 d.术后2、7(用药前)、14、21、28、35、42 d测量各组瘢痕疙瘩组织块体积;术后42 d取出瘢痕疙瘩组织块,HE染色进行组织学检查,末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法检测成纤维细胞凋亡情况,免疫组织化学染色检测Bcl-2、Bax蛋白质的表达.结果 用药前和用药后7、14、21、28、35 d,D组瘢痕疙瘩组织块体积(mm3)分别为173±5、172±5、147±5、125±6、112±7和84±9,从用药后14 d开始明显缩小(均P＜0.05);而其他3组瘢痕疙瘩组织块体积均明显增大,从用约后7 d开始各时点测得的体积均明显大于D组(均P＜0.05).D组瘢痕疙瘩组织中有大量小鼠组织细胞浸润,胶原结构破坏和成纤维细胞凋亡明显重于其他3组,Bcl-2蛋门质表达明显弱于而Bax蛋白质表达明显强于其他3组.结论 腺病毒介导的CDglyTK双自杀基因系统在瘢痕疙瘩裸鼠模型中对瘢痕疙瘩产生治疗作用,诱导成纤维细胞凋亡足其主要作用机制.

Effects of recombinant adenovirus-mediated double suicide genes on implanted human keloid: experiment with athymic mice

Objective To detect the effects of the recombinant adenovirus-mediated double suicide genes constructed by Escherichia coli cytosine deaminase (CD)/5-fluorocytosine (5-Fc) and herpes simplex virus-thymidine kinase (HSV-TK)/ganiclovir (GCV)-CDglyTK on implanted human keloids and mechanisms thereof.Methods Twenty nude mice were implanted with human keloid obtained during operation so as to establish mouse keloid models and then were randomly divided into 4 equal groups :Group A, injected with normal saline (NS) into the keloid once per 3 days for 18 days totally, Group B injected with NS into the keloid and injected intraperitoneally with 5-Fc and GCV;Group C injected with CDglyTK into the keloid, and Group D injected with CDglyTK into the keloid aud 5-Fc and GCV injected intraperitoneally.The volume of the implanted keloid tissue was measured 2, 7, 14, 21, 28, 35, and 42 days after operation.On day 42 the keloid tissues were removed to undergo morphological examination, TUNEL method was used to examine the apeptosis of the fibroblasts, and the expression of Bcl-2 and BAX, products of apoptosis-related genes, were detected by immunohistochemistry.Results Compared to those before treatment the volume of the implanted keloid of Group D began to decrease since 14 days after treatment time-dependently (all P < 0.05), and the volumes of the other 3 groups continued to increase and peaked on days 21, 14, or 7 respectively (all P < 0.05).Microscopy showed infiltration of a larger quantity of histiocyte in the keloid tissue, and more obvious collagen disorganization and apoptosis of fibroblasts in Group D than in the other 3 groups.The protein expression of Bcl-2 was more remarkable and the protein expression of BAX was less remarkable in Group D than iu the other 3 groups.Condusions The recombinant adenovirus-mediated double suicide gene therapy is effective on the implanted keloid tissue.The main mechanism may be induction of apoptosis in the keloid fibroblasts.