本文選題：CT + DNA雙鏈斷裂�。� 參考：《南京大學(xué)》2017年碩士論文

【摘要】：第一部分CT檢查對外周血淋巴細(xì)胞DNA雙鏈斷裂影響的研究目的:評價腹部CT增強(qiáng)檢查對外周血淋巴細(xì)胞內(nèi)DNA雙鏈斷裂(double strand breaks,DSBs)水平的影響。材料與方法:選取12例健康志愿者,各抽取8 ml靜脈血,將每例志愿者的靜脈血分為A組、B組、C組和D組,每組2 ml血液,進(jìn)行體外實驗;其中A組外周血作為對照組,不接受CT掃描;B-D組外周血接受相當(dāng)于1、2、3次腹部CT輻射劑量的掃描。選取30例腹部增強(qiáng)CT檢查的患者進(jìn)行體內(nèi)實驗。在CT檢查前(基線組)及檢查后5 min(輻射組)分別抽取2ml靜脈血,并記錄劑量長度乘積(dose-length product,DLP)和 CT 容積劑量指數(shù)(volume CT dose index,CTDIvol)。所有血樣通過淋巴細(xì)胞分離及γ-H2AX蛋白的免疫熒光染色,標(biāo)記出DSBs。通過重復(fù)測量方差分析比較A、B、C、D組間DSBs水平的關(guān)系。通過配對樣本t檢驗比較基線組和輻射組間DSBs水平的關(guān)系。采用Pearson相關(guān)分析分析體內(nèi)實驗組輻射劑量與γ-H2AX焦點增加的關(guān)系。結(jié)果:在體外試驗中,接受CT輻射暴露的B、C、D組血樣中DSBs水平均較A組明顯升高,升高幅度分別為49.4%、96.6%和149.4%(所有P0.001),且輻射劑量分組與DSBs水平存在線性趨勢(P0.001)。在體內(nèi)實驗中,CT檢查前γ-H2AX焦點的平均值及標(biāo)準(zhǔn)差為0.62±0.35焦點/細(xì)胞,檢查后為0.89±0.42焦點/細(xì)胞,輻射組血樣中淋巴細(xì)胞內(nèi)DSBs水平較基線組DSBs水平升高約43.5%(P0.001);但CT檢查后DSBs的增加量與DLP或CTDIvol未發(fā)現(xiàn)明顯相關(guān)性。結(jié)論:外周血淋巴細(xì)胞內(nèi)DSBs水平在進(jìn)行腹部CT增強(qiáng)檢查后明顯升高,體外研究表明CT檢查輻射劑量與細(xì)胞內(nèi)DSBs水平存在線性趨勢。第二部分口服維生素C預(yù)防CT檢查后DNA雙鏈斷裂的研究目的:研究口服維生素C對腹部對比增強(qiáng)CT檢查后患者外周血中DNA雙鏈斷裂(double strand breaks,DSBs)損傷的預(yù)防作用。材料與方法:本研究共入組60例腹部對比增強(qiáng)CT檢查患者,分為對照組(30例)及預(yù)防組(30例)。預(yù)防組在CT檢查前30～120 min 口服1 g維生素C,對照組不使用任何藥物。預(yù)防組根據(jù)口服維生素C時間點的不同分為3組(30 min,n=16;60min,n=10;120min,n=4)。所有患者在CT檢查前及檢查后5 min抽取2 ml外周血。將所有血樣分離出淋巴細(xì)胞,進(jìn)行免疫熒光染色,標(biāo)記出細(xì)胞核內(nèi)的代表DSBs的y-H2AX熒光焦點。兩組間的計數(shù)資料(包括性別和合并癥)的組間比較使用卡方檢驗。兩組間計量資料,包括劑量長度乘積(dose-length product,DLP)、CT容積劑量指數(shù)(volume CT dose index,CTDIvol)、y-H2AX焦點基線水平間的比較使用t檢驗及u檢驗。不同時間點口服維生素C的預(yù)防組間γ-H2AX焦點增加的差異性使用ANOVA檢驗。輻射劑量與γ-H2AX焦點增加的關(guān)系使用Pearson相關(guān)及Spearman相關(guān)分析。結(jié)果:對照組和預(yù)防組兩組間的CTDIvol及DLP沒有統(tǒng)計學(xué)差異(P值均0.05)。對照組檢查后γ-H2AX焦點較檢查前平均增加0.49個/細(xì)胞,預(yù)防組檢查后平均增加0.19個/細(xì)胞,檢查后預(yù)防組較對照組y-H2AX焦點增加量顯著減少(p0.001),減少量占對照組增加量的61%。在預(yù)防組中,γ-H2AX焦點增加量分別與DLP及CTDIvol呈顯著相關(guān)(r值分別為0.449和0.403,P值均0.05)。不同時間點口服維生素C的預(yù)防組間γ-H2AX焦點增加沒有表現(xiàn)出差異性(所有P0.05)。結(jié)論:檢查前口服維生素C能夠顯著減少腹部對比增強(qiáng)CT檢查后的DSBs水平,對CT所致的DNA損傷起到一定保護(hù)作用。
[Abstract]:The first part of CT examined the effect of DNA double strand breaks on peripheral blood lymphocytes. Objective: To evaluate the effect of abdominal CT enhancement on the level of DNA double strand breaks (double strand breaks, DSBs) in peripheral blood lymphocytes. Materials and methods: 12 healthy volunteers were selected to take 8 ml venous blood each, and the venous blood of each volunteer was divided into A group. In group B, group C and group D, each group of 2 ml blood was tested in vitro, and the peripheral blood of group A was taken as the control group and no CT scan was accepted; the peripheral blood of the group B-D received the equivalent of the CT radiation dose in the abdomen of 1,2,3 times. The patients of the abdominal enhanced CT examination were selected in the body experiment. Before CT examination (baseline group) and after examination 5 min (radiation groups) were extracted 2, respectively. Ml venous blood was recorded and the dose length product (dose-length product, DLP) and CT volume dose index (volume CT dose index, CTDIvol) were recorded. All blood samples were stained by lymphocyte separation and immunofluorescence staining of gamma -H2AX protein. The relationship between the baseline group and the DSBs level between the radiation groups was compared. The relationship between the radiation dose of the experimental group and the increase of the focus of gamma -H2AX was analyzed by Pearson correlation analysis. Results: in the in vitro test, the levels of DSBs in the B, C and D groups receiving CT radiation exposure were significantly higher than those in the A group, and the elevation was 49.4%, 96.6% and 149.4% respectively (all P0.001), respectively. And there was a linear trend (P0.001) in the radiation dose group and the DSBs level. In the experiment in vivo, the average value and standard deviation of the focus of gamma -H2AX before CT examination were 0.62 + 0.35 focus / cell, and 0.89 + 0.42 focus / cell after examination. The level of DSBs in the lymphocyte of radiation group increased by 43.5% (P0.001) than that in the baseline group (P0.001); but DSBs after CT examination, DSBs There was no significant correlation between the increase of DLP or CTDIvol. Conclusion: the level of DSBs in peripheral blood lymphocytes increased significantly after abdominal CT enhanced examination. In vitro studies showed that there was a linear trend in the radiation dose of CT and the level of intracellular DSBs. The second part of the study was to study the aim of the study of DNA double strand breaks after the oral vitamin C pre control of CT. Study the preventive effect of oral vitamin C on DNA double strand breaks (double strand breaks, DSBs) injury in peripheral blood of patients after abdominal contrast enhanced CT examination. Materials and methods: 60 cases of abdominal contrast enhanced CT examination were included in this study. The control group was divided into control group (30 cases) and prevention group (30 cases). The prevention group had 1 g 30~120 min before CT examination. The prevention group was divided into 3 groups (30 min, n=16; 60min, n=10; 120min, n=4) according to the time points of oral vitamin C. All the patients were extracted with 2 ml peripheral blood before and after the examination of CT. All the blood samples were separated from the lymphocytes, and the immunofluorescence staining was carried out to mark out the DSBs in the nucleus. Fluorescent focus. The count data between groups of two groups (including sex and complication) were compared with the chi square test. Two groups of measurement data, including the dose length product (dose-length product, DLP), the CT volume dose index (volume CT dose index, CTDIvol), and the comparison between the y-H2AX focus baseline level using t test and U test. The differential use of ANOVA test for the increase of gamma -H2AX focus between the prevention groups of vitamin C was used. The relationship between the radiation dose and the increase of gamma -H2AX focus was associated with Pearson and Spearman related analysis. Results: there was no statistical difference between the two groups of the control group and the prevention group, CTDIvol and DLP (P is 0.05). The focus of gamma -H2AX after the control group was compared to the check before the check. The increase of 0.49 / cell was increased by 0.49 / 0.19 cells, and the increase in the focus of the prevention group was significantly reduced (p0.001), and the decrease in the amount of 61%. in the control group was significantly correlated with DLP and CTDIvol (R values were 0.449 and 0.403, P values were 0.05 respectively). The increase of gamma -H2AX focus between the prophylactic group of oral vitamin C at the same time did not show a difference (all P0.05). Conclusion: oral vitamin C before examination can significantly reduce the level of DSBs after abdominal contrast-enhanced CT examination, and can play a protective role in DNA damage caused by CT.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R816
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本文編號：1957101