發(fā)布時間：2018-06-03 04:48

  本文選題：納米二氧化鈦 + 睪酮��； 參考：《山西農(nóng)業(yè)大學(xué)》2013年碩士論文

【摘要】：[目的]納米二氧化鈦作為一種遮光劑,在各種化妝品涂料中廣泛應(yīng)用。近來研究表明,納米顆粒的攝入會導(dǎo)致人睪酮水平發(fā)生改變。本文利用RT-PCR, Western-blot,透射電鏡,組織切片等方法,結(jié)合精子活率,畸形率,血清睪酮含量的變化等情況,綜合分析納米二氧化鈦對青春期小鼠雄性生殖的影響,并對其可能機制進行研究。 [方法]4周齡雄性昆明小鼠40只,隨機分為四組：對照組,低劑量組,中劑量組和高劑量組。自由飲水和采食,每天稱重灌胃。具體劑量如下：配置含0.5%Tween80的PBS緩沖液。對照組灌服不含Nano-TiO2的緩沖液,低劑量組灌服含10mg/kgNano-TiO2的緩沖液,中劑量組灌服含50mg/kgNano-TiO2的緩沖液,高劑量組灌服含250mg/kgNano-TiO2的緩沖液。灌胃期間觀察記錄各組小鼠的活動,被毛及體重等變化情況。42天后,眼球采血,取睪丸組織分別進行RT-PCR, Western-blot,以及組織病理學(xué)切片等試驗；并結(jié)合精子密度,畸形率等變化情況,綜合評估納米二氧化鈦對小鼠生殖系統(tǒng)的影響。 [結(jié)果]1.與對照組相比,各納米二氧化鈦暴露組的小鼠體重均有所下降,高劑量組的體增重與對照組相比明顯降低,差異顯著。各攻毒組睪丸、附睪的臟器指數(shù)與對照組相比,無顯著性差異。 2.各組小鼠精子密度相比,無顯著性差異。與對照組相比,各實驗組小鼠精子活率和血清睪酮呈降低趨勢,中高劑量組差異顯著。與此相反,各攻毒組小鼠畸形率與對照組相比有所上升,其中,中高劑量組差異顯著。 3.睪丸組織病理學(xué)切片結(jié)果顯示,對照組睪丸組織的曲細精管結(jié)構(gòu)完整,各級生精細胞排列整齊,可見到大量的成熟精子。低劑量組精子細胞有所減少,曲細精管間隙增大。中高劑量組各級生精細胞明顯減少,細胞排列不規(guī)則,管腔塌陷,曲細精管間有空泡形成。透射電鏡結(jié)果顯示：納米二氧化鈦可導(dǎo)致睪丸線粒體膨大,內(nèi)部嵴消失。 4.應(yīng)用RT-PCR對小鼠睪丸中StAR、P450-17α、17β-HSD、3p-HSD、Cyp19、P450scc、AR和GATA-4的nRNA表達水平分析得知：與對照組相比,三個劑量組睪丸GATA-4、17β-HSD的mRNA表達均顯著降低,中、高劑量組睪丸P450-17a的mRNA表達顯著降低；高劑量組Cyp19mRNA表達量顯著升高；其它基因mRNA表達無顯著性差異。 5.用Western-blot對各組小鼠睪丸組織的P450-17α、17β-HSD和Cyp19的蛋白表達量進行分析可知：與對照組相比,高劑量組P450-17a的蛋白表達量顯著降低；中、高劑量組17β-HSD的蛋白表達量顯著降低。與此相反,Cyp19的蛋白表達量則呈升高的趨勢,且中、高劑量組與對照組相比,差異顯著。 [結(jié)論]實驗中,睪酮合成過程中的關(guān)鍵基因P450-17α、17β-HSD表達水平在基因和蛋白水平有不同程度的下降；同時,Cyp19的表達顯著升高。說明納米二氧化鈦通過兩方面的作用影響雄性小鼠的睪酮含量進而導(dǎo)致其生殖功能的下降：一方面,Nano-TiO2抑制了小鼠睪酮合成通路上P450-17a和17β-HSD基因表達來降低睪酮的合成；另一方面,Nano-TiO2刺激了小鼠睪丸中雌激素的生成,導(dǎo)致了雌雄激素比例失調(diào)。
[Abstract]:[Objective] nanoscale titanium dioxide is widely used in various cosmetic coatings as a kind of light shading agent. Recent studies have shown that the intake of nanoparticles will lead to changes in the level of human testosterone. This paper uses RT-PCR, Western-blot, transmission electron microscopy, tissue section and other methods, combined with the survival rate, deformity rate, and serum testosterone content, and so on. The effects of nano titanium dioxide on male reproduction in puberty mice were comprehensively analyzed and its possible mechanism was studied.
[Methods] 40 male Kunming mice were randomly divided into four groups: the control group, the low dose group, the middle dose group and the high dose group. The free drinking water and the high dose group were weighed every day. The specific dosage was as follows: the PBS buffer containing 0.5%Tween80 was assigned to the control group. The control group was filled with the gentle punching solution without Nano-TiO2, and the low dose group was given the buffer of 10mg/kgNano-TiO2 containing 10mg/kgNano-TiO2 In the medium dose group, the buffer solution containing 50mg/kgNano-TiO2 was perfused, and the high dose group was given the buffer solution containing 250mg/kgNano-TiO2. During the period of gavage, the activities of the mice were recorded and the eyeball was collected after.42 days after the changes of hair and weight. The testis tissues were taken RT-PCR, Western-blot, and histopathological sections respectively. The effects of nano titanium dioxide on reproductive system of mice were comprehensively evaluated.
[results compared with the control group, the weight of mice in the nanoscale titanium dioxide exposure group decreased and the body weight gain of the high dose group decreased significantly compared with the control group. There was no significant difference in the visceral index of the testis and epididymis of the attack group compared with the control group.
2. the sperm density of mice in each group had no significant difference. Compared with the control group, the sperm motility and serum testosterone of the mice in the experimental groups were decreased, and the difference in the middle and high dose groups was significant.
3. the pathological sections of the testicular tissue showed that the structure of the seminiferous tubules in the testicular tissue of the control group was complete, the spermatogenic cells at all levels were arranged neatly, and a large number of mature spermatozoa were found. The low dose group was reduced and the space of the fine tubule increased. The fine cells in the middle and high dose groups decreased obviously, the cell arrangement was irregular, the lumen collapsed, and the curve was collapsed. There was vacuolization between seminiferous tubules. Transmission electron microscopy showed that nano-TiO2 could cause testicular mitochondria to expand and internal cristae disappear.
4. the expression level of StAR, P450-17 alpha, 17 beta -HSD, 3p-HSD, Cyp19, P450scc, AR and GATA-4 in mice testis was analyzed. The expression of GATA-4,17 beta -HSD in the three doses group decreased significantly compared with the control group, and the expression of the testis in the high dose group was significantly lower than that in the control group. The expression of mRNA was not significantly different.
5. the protein expression of P450-17 alpha, 17 beta -HSD and Cyp19 in each group of mice was analyzed with Western-blot, and the protein expression of P450-17a in high dose group decreased significantly compared with the control group; in the high dose group, the protein expression of 17 beta -HSD decreased significantly. In contrast, the expression of Cyp19 protein showed an increasing trend. The difference between the high dose group and the control group was significant.
[Conclusion] in the experiment, the key gene P450-17 alpha and 17 beta -HSD in the process of testosterone synthesis decreased in varying degrees in genes and protein levels; meanwhile, the expression of Cyp19 was significantly increased. It indicated that the effect of nano titanium dioxide on the testosterone content of male mice and the decrease of reproductive function in male mice, on the one hand, was on the one hand. Nano-TiO2 inhibits the expression of P450-17a and 17 beta -HSD gene in the mouse testosterone synthesis pathway to reduce the synthesis of testosterone; on the other hand, Nano-TiO2 stimulates the formation of estrogen in the testis of mice and leads to the imbalance of male and female hormones.
【學(xué)位授予單位】：山西農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：R114

【共引文獻】

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2 夏露;膽固醇轉(zhuǎn)運相關(guān)基因在鵝卵泡類固醇激素合成中的作用研究[D];四川農(nóng)業(yè)大學(xué);2013年

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本文編號：1971526