AIM: To evaluate the local expression of CTLA4 Ig gene in small bowels and its effect on preventing acute rejection of the small bowel allografts. METHODS: Groups of Wistar rats underwent heterotopic small bowel transplantation from SD rats. The recipients were randomly divided into experimental group (allografts were transfected with CTLA4Ig gene) and control group (non CTLA4Ig gene transfected). In the experimental group, the donor small bowels were perfused ex vivo with CTLA4Ig cDNA packaged with lipofectin vector via intra-superior mesenteric artery before transplantation, and the CTLA4Ig expression in the small bowel grafts post-transplantation was assessed by immunohistology. On d 3, 7 and 10 posttransplantation, the allografts in each group were harvested for the examination of histology and detection of apoptosis. RESULTS: Small bowel allografts treated with CTLA4Ig Cdna showed abundant CTLA4Ig expression after transplantation. Acute rejection of grade I on d 7 and grade II on d 10 after transplantation was noticed in the control allografts, and a dramatically increased number of apoptotic enterocytes in parallel to the progressive rejection could be recognized. In contrast, the allografts treated with CTLA4Ig cDNA showed nonspecific histological changes and only a few apoptotic enterocytes were found after transplantation. CONCLUSION: Local CTLA4Ig gene transfection of small bowel allograft is feasible, and the local CTLA4Ig expression in the allograft can prevent acute rejection after transplantation.

目的：通过检测IFN-γ基因转染对大肠癌细胞表面抗原的表达情况、对细胞的生长抑制、细胞周期的影响情况，初步探讨IFN-γ基因治疗抗肿瘤作用的机制。方法：制备含人IFN-γ基因的真核表达质粒pcDNA-3-IFN-γ，利用阳离子脂质体将其转染进入人大肠癌细胞株LOVO、SW62O、HCT116BG 及人宫颈癌细胞株Hela，检测基因转染后IFN- γ基因的表达情况，同时检测基因转染对大肠癌细胞CEA、HLA-DR 抗原表达的诱导作用和细胞凋亡及细胞周期的变化。结果：基因转染后，原来高表达CEA 的细胞株(LOVO、HCT116BG)其上清中CEA含量增加明显(从21.25±6.76 μ/l增加到34.96±7.07 μg/l P <0.05)，而原来低表达甚至不表达CEA的细胞株(Hela、SW620)其上清CEA含量则无明显增加 (P >0.05)。各细胞株表面的HLA-DR 的表达量在导入IFN- γ基因后明显增强(平均表达率从3.91±3.61 % 增加到11.67±7.20 % P <0.01)。通过对细胞的凋亡情况和细胞周期的变化显示：转染IFN-γ基因后促进了LOVO细胞的凋亡(各时段平均凋亡率对照组与治疗组分别为8.27±5.62 %与15.32±11.41% P <0.05)，细胞的S 期比例随作用时间延长而呈逐渐降低趋势，显示了基因转染后DNA的合成代谢受到抑制。结论：IFN-γ基因转染后可有效增强大肠癌细胞表面抗原的表达，诱导机体产生抗肿瘤免疫应答；并可能通过抑制细胞DNA的合成，促进细胞的凋亡，抑制肿瘤细胞的增生等机制发挥抗肿瘤作用。

Dendritic cells (DC) constitute a complex system of uniquely specialized antigen-presenting cells (APC) that play crucial roles in the initiation and regulation of immune responses. Recent studies have demonstrated that DC silenced by siRNA IL-12 p35 showed tolerogenic capacity in vitro. However, their mechanism of action is not fully understood. In this study, IL-12p35 siRNA was chemically synthesized and transfected into DCs. A coculture of T cells and DCs was performed. After 30 min coculture, T cells were harvested and analyzed. We showed that the IL-12 p35 silenced DCs decreased IL-12-induced T cell responses through blocking tyrosine phosphorylation of JAK2, TYK2, STAT3, and STAT4 proteins in T cells. These results demonstrate IL-12 p35 silenced DCs modulate immune responses by blocking IL-12 signaling through JAK-STAT pathway in T cells.

AIM: To evaluate the feasibility of laparoscopic resection of rectal carcinoma and to compare the short-term outcome of laparoscopic procedure with conventional open surgery for rectal cancer.