严重烧伤大鼠胸腺诱导型一氧化氮合酶表达对细胞凋亡的影响  

Influence of induced nitric oxide synthase expression on apoptosis of thymocyte in burn rats

作　　者：胡章颜[1] 程上穆[2] 朱清仙[2] 

机构地区：[1]浙江绍兴文理学院医学院解剖学教研室,312000 [2]南昌大学医学院组织胚胎学教研室

出　　处：《中华烧伤杂志》2006年第6期419-422,共4页Chinese Journal of Burns

摘　　要：目的观察严重烧伤大鼠胸腺诱导型一氧化氮合酶(iNOS)表达对胸腺细胞凋亡的影响,探讨一氧化氮(NO)与胸腺病理损害的关系。方法将56只雄性Wistar大鼠随机分为对照组(8只)、烧伤组(24只)、烧伤+硫酸甲基异硫脲(SMT)组(24只)。后两组大鼠背部造成30％TBSAⅢ度烧伤,伤后分别立即静脉注射等渗盐水、等渗盐水+SMT(7．5 mg／kg);对照组不予烧伤及SMT处理。两烧伤组分别于伤后6、24、72 h检测胸腺重量、胸腺细胞凋亡情况(原位缺口末端标记法)、胸腺iNOS表达情况(免疫组织化学染色法),采用体视学方法测定阳性细胞密度,每时相点8只;同时测定对照组相应指标。结果烧伤组大鼠伤后24、72 h胸腺重量分别为(153±14)、(91±22)mg,明显轻于对照组[(243±12)mg,P<0．01];烧伤+SMT组此时明显高于烧伤组(P<0．01)。对照组大鼠胸腺皮、髓质可见散在少量凋亡阳性细胞、iNOS阳性细胞。烧伤组大鼠伤后6 h胸腺皮质有凋亡阳性细胞及少量iNOS阳性细胞;伤后24 h时凋亡阳性细胞分布于被膜下皮质、皮髓交界处及髓质,iNOS阳性细胞广泛出现在小叶间隔内血管旁;伤后72 h时凋亡阳性细胞使胸腺皮质广泛呈现棕褐色;伤后6～72 h烧伤组iNOS阳性细胞呈进行性增加(P<0．05)。烧伤+SMT组大鼠伤后各时相点阳性细胞较少且分布不均,凋亡灶少见,未见iNOS阳性细胞。烧伤组大鼠伤后24、72 h凋亡阳性细胞密度分别为(2．428±0．728)×10-5／μm3、(5．586±1．233)×10-5／μm3,高于对照组和烧伤+ SMT组(P<0．01)。结论严重烧伤大鼠伤后早期胸腺细胞凋亡率增加,iNOS在胸腺表达增强并促进了胸腺细胞凋亡;SMT则能部分改善这一现象。Objective To investigate the influence of induced nitric oxide synthase （iNOS） expression on apoptosis of thymoeyte in burn rats, and to explore the relationship between NO and pathological lesion of the thymus gland in burn rats. Methods Fifty-six male Wistar rats were enrolled in the study and randomized into control（ C, n = 8,without treatment）, burn （ B, n = 24） , and S-methylisothiourea（ SMT, n = 24） groups. Equal amount of isotonic saline solution and SMT（ 7.5 mg/kg） were respectively intraveously infused into the rats in B and SMT groups after being inflicted with 30% TBSA full-thickness burns. The weight of thymus gland in each group were weighed, and thymoeyte apoptosis and iNOS expression were determined with TUNEL method and immunohistoehemistry, respectively at 6,24,72 postburn hours（ PBH）, with 8 rats at each time-point. The number of apoptotie cells and the density of iNOS positive cells in thymus was measured by stereologieal method. Results The weight of thymus in B group at 24 and 72 PBHE （ 153 ± 14 ）, （91 ±22）mg] were obviously heavier than those in C group, but much lighter than those in SMT group （ P 〈 0.01）. A few apoptotie cells and iNOS positive cells were observed in cortex and medulla of thymus in C group, while they were observed in B group at 6 PBH, and the number of cells began to increase at 24 PBH, distributing in medulla,parenehyma, the boundary of cortex, and medulla under capsule. The iNOS positive cells in B group at 24 PBH were distributed around the interlobular septum. A large number of cortical cells with brown stainning were observed in B group at 72 PBH, and the number of iNOS positive cells also increased, with scattered distribution and clear cell boundary. Fewer positive cells with uneven distribution, no iNOS positive cells, and few apoptotie loci were observed in SMT group after burns. The density of apoptotie cells in B group at 24 and 72 PBH was （ 2.428 ± 0. 728 ） × 10 - ^-5/μm^3 and （ 5. 586 ± 1. 233 ）

关 键 词：烧伤 细胞凋亡 胸腺 诱导型一氧化氮合酶 

分 类 号：R644[医药卫生—外科学]