【摘要】：重金屬污染不僅影響工農(nóng)業(yè)的生產(chǎn),而且可以通過食物鏈的富集作用,蓄積到人體內(nèi),對人類健康造成嚴(yán)重的危害。鎘是一種主要蓄積在肺臟、肝臟、腎臟、骨骼、生殖系統(tǒng)和免疫系統(tǒng)中的有毒污染物,其對組織的毒性主要包括腎毒性、致癌、致畸和內(nèi)分泌干擾。本研究首先分析了漢江漢中段鯉魚、青魚、泥鰍、鯽魚、生魚、鯰魚、鰱魚7種淡水魚肝、鰓和肌肉中鎘的分布。然后在實驗條件下,以鎘作為實驗用毒,以鯽魚作為實驗動物,使用靜態(tài)染毒法進(jìn)行毒理學(xué)實驗。共設(shè)置3組鎘濃度梯度,1個空白對照組,每組設(shè)置兩組平行實驗。染毒10 d后,采用H·E染色法和SABC免疫組化染色法探討了鯽魚的消化道組織學(xué)與消化道內(nèi)分泌細(xì)胞密度變化。結(jié)果表明,漢江漢中段常見7種淡水魚中,檢測的3種器官中,平均鎘含量分布順序由高到低是肝臟鰓肌肉。其中7種魚的鰓和肝臟中鎘含量都超標(biāo),但肌肉中鎘含量較低,僅泥鰍和鯉超出標(biāo)準(zhǔn)。組織學(xué)觀察顯示,鯽魚腸道由內(nèi)到外可分為4層,分別是粘膜層、粘膜下層、肌層和外膜層,組織學(xué)結(jié)構(gòu)上染毒組與空白組沒有顯著差異。免疫組化結(jié)果顯示,胃泌素細(xì)胞、生長抑素細(xì)胞、血管活性腸肽細(xì)胞在鯽魚整個腸道中都有分布,胃泌素細(xì)胞和生長抑素細(xì)胞的密度由前腸到后腸遞減,在不同部位的密度達(dá)到了顯著差異。血管活性腸肽細(xì)胞的分布規(guī)律與胃泌素細(xì)胞和生長抑素細(xì)胞類似,但各腸段密度上沒有顯著差異。P物質(zhì)細(xì)胞僅在中腸分布,促胰液素細(xì)胞僅分布在前腸。在鎘暴露10d之后,鯽魚腸道組織學(xué)結(jié)構(gòu)沒有明顯變化,但消化道內(nèi)分泌細(xì)胞的密度發(fā)生了變化。隨著染毒鎘濃度的增加,胃泌素細(xì)胞、血管活性腸肽細(xì)胞的密度呈上升趨勢;生長抑素、P物質(zhì)、促胰液素細(xì)胞的密度呈下降趨勢。與對照組相比,胃泌素細(xì)胞密度的上升在前腸和中腸有顯著性差異,血管活性腸肽細(xì)胞密度的上升僅在后腸有顯著性差異,而生長抑素細(xì)胞密度的下降僅在前腸差異顯著。P物質(zhì)細(xì)胞和促胰液素細(xì)胞的密度下降都達(dá)到了顯著性差異。通過討論,得出下列結(jié)論:漢江漢中段淡水魚有一定程度的鎘蓄積現(xiàn)象,并且部分魚肌肉鎘含量超標(biāo),不可食用。水環(huán)境鎘濃度在5.00 mg/L以內(nèi)時,10 d的鎘暴露對鯽魚消化道沒有造成顯著的組織學(xué)損傷,但造成了鯽魚消化道內(nèi)分泌細(xì)胞的分布密度改變。水中鎘濃度與消化道內(nèi)分泌細(xì)胞密度呈顯著相關(guān)關(guān)系。鎘對消化道內(nèi)分泌細(xì)胞的影響受多種機(jī)制調(diào)控,不僅與鎘的腎毒性、肝毒性有關(guān),也與內(nèi)分泌細(xì)胞間相互的調(diào)控有關(guān)。
[Abstract]:Heavy metal pollution not only affects the production of industry and agriculture, but also accumulates into human body through the enrichment of food chain, which causes serious harm to human health. Cadmium is a toxic pollutant mainly accumulated in lung, liver, kidney, skeleton, reproductive system and immune system. Its toxicity to tissues mainly includes nephrotoxicity, carcinogenesis, teratogenicity and endocrine disruptions. The distribution of cadmium in liver, gills and muscles of Carp, herring fish, Loach, Carassius auratus, Raw fish, catfish and silver carp in Hanzhong section of Hanjiang River was analyzed. Under the experimental conditions, cadmium was used as experimental poison and crucian carp as experimental animal. Three groups of cadmium concentration gradient, one blank control group, two groups of parallel experiments were set up in each group. After 10 days of exposure, the changes of digestive tract histology and endocrine cell density of crucian carp were studied by H E staining and SABC immunohistochemical staining. The results showed that the average cadmium content in the three organs of 7 freshwater fishes in Hanzhong section of Hanjiang River was liver Gill muscle from high to low. The contents of cadmium in Gill and liver of 7 species of fish were above the standard, but the content of cadmium in muscle was lower, only Loach and common carp exceeded the standard. Histological observation showed that the intestinal tract of Carassius auratus could be divided into four layers from inside to outside, which were mucosal layer, submucosal layer, muscular layer and outer membrane layer. There was no significant difference in histologically and structurally between exposed group and blank group. Immunohistochemical results showed that gastrin cells, somatostatin cells and vasoactive intestinal peptide cells were distributed in the whole intestine of crucian carp, and the density of gastrin cells and somatostatin cells decreased from foregut to hindgut. There were significant differences in density between different parts. The distribution of vasoactive intestinal peptide cells was similar to that of gastrin cells and somatostatin cells, but there was no significant difference in the density of each intestinal segment. After 10 days of cadmium exposure, the intestinal histological structure of crucian carp did not change significantly, but the density of endocrine cells in digestive tract changed. With the increase of cadmium concentration, the density of gastrin cells and vasoactive intestinal peptide cells increased, and the density of somatostatin, substance P and trypsin cells decreased. Compared with the control group, the increase of gastrin cell density was significant in the foregut and midgut, while the increase of vasoactive intestinal peptide cell density was only significant in the hindgut. However, the decrease of somatostatin cell density was only significant in the foregut. Through discussion, the following conclusions are drawn: fresh water fish in the middle section of Han Jianghan have a certain degree of cadmium accumulation, and some of the fish muscle cadmium content exceeds the standard, so it is not edible. When the concentration of cadmium in water was less than 5.00 mg/L, cadmium exposure for 10 days did not cause significant histological damage to the digestive tract of crucian carp, but resulted in the change of distribution density of endocrine cells in digestive tract of crucian carp. There was a significant correlation between the concentration of cadmium and the density of endocrine cells in digestive tract. The effects of cadmium on endocrine cells in digestive tract are regulated by many mechanisms, not only related to the nephrotoxicity and hepatotoxicity of cadmium, but also to the regulation of endocrine cells.
【學(xué)位授予單位】：陜西理工學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S917.4;X503.225

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