探討重金屬鉛對於出生後離乳大白鼠門齒萌發率之影響

Effects of Lead on the Eruption Rates of Incisor in Developing Rats

柯嘉泠(Chia-Ling , Ko)

指導教授 ： 陳弘森

高雄醫學大學/口腔醫學院/口腔衛生科學研究所碩士班/碩士(2008年)

https://doi.org/10.6832/KMU.2008.00137

摘要

背景：
鉛(lead)從幾千年前即被人類廣泛應用，近年來在環境衛生與職業醫學領域的鉛研究報告顯示，鉛暴露對於人體的影響大多是有害的，雖然現在對於鉛的毒性已了解不少，但多半是針對孩童的智力發展、認知、行為、神經系統損傷等，國內對於鉛經由懷孕婦女對胎兒在牙齒構造及萌發過程的影響，包含細胞或組織結構上的異常等並無相關研究。

目的：
要研究鉛暴露對人類胎兒牙齒發育的影響，有其困難度，所以本研究透過實驗動物模式，利用不同的懷孕母鼠(outbred stock Wistar rat)分別於懷孕期及哺乳期的飲水鉛暴露，來了解於懷孕期及哺乳期的鉛暴露對於出生後離乳大白鼠門齒萌發所造成的影響。

方法：
在本實驗中將不同的懷孕母鼠分為五組，對照組為未受任何處置的懷孕母鼠；其他四組分別於懷孕期及哺乳期進行高低劑量的鉛暴露(50ppm、200ppm)，再測量這五組出生後離乳大白鼠的門齒萌發 情形，並將出生後離乳大白鼠犧牲後，製作切片以光學顯微鏡來觀察。

結果：
結果顯示哺乳期暴露不論暴露低劑量或高劑量的鉛皆會使得門齒萌發速率有減緩的情形，哺乳期低劑量組門齒萌發長度為1.44mm(標準差為±0.53mm)，而高劑量組為1.18mm (±0.23mm)。而懷孕期50ppm與200ppm的出生後離乳大白鼠門齒萌發率皆與對照組無顯著差異，對照組的出生後離乳大白鼠奇門齒萌發長度為1.67mm(標準差為±0.33mm)，懷孕期鉛暴露50ppm者，其萌發長度為1.57mm(±0.65mm)；為懷孕期鉛暴露200ppm者，其萌發長度為1.54mm(±0.17mm)。在組織型態上可看到哺乳期的暴露組odontoblasts layer厚度較薄且細胞排列較為鬆散，懷孕期的暴露組則有odontoblasts layer邊緣較為不規則及不平順的情形出現。

結論：
所以我們推論幼鼠會對於出生後的鉛暴露感受性較強且對於門齒萌發的影響也較懷孕期來得明顯。其實不論是懷孕期或哺乳期的鉛暴露，其實對於年幼的孩童來說，他們對於鉛暴露都較為敏感，應該要儘量減低鉛暴露的可能性，避免孩童遭受到鉛毒性的危害。

關鍵字

鉛 ； 牙齒 ； 大白鼠 ； 門齒萌發率

並列摘要

Project background
Lead is a heavy soft metal of dull grayish color, which is usually employed in many industries. According to many research reports, the influence of lead to human body is mostly harmful. It was well known that the toxicity of lead could affect children’s intelligence quotient, cognition and behavior patterns. There are limited data in Taiwan concerning about the effects of lead through pregnant women to babies and how it would affect newborn baby’s tooth structure, eruption rates and enamel formation.

Project objectives
The present study was performed to describe the effects of lead exposure during test animal subject’s pregnancy and lactation stages and on the developing teeth of newborn rats. The objective of this study was to investigate the effects of lead exposure during pregnancy and lactation in the tissue and structure of newborn rat’s incisors and eruption rates of the incisor.

Materials and methods
This project was performed using laboratory animal models. The laboratory animals used were the outbred stock pregnant Wistar rats. They were exposed to low and high dosage lead (50ppm and 200ppm, respectively) during pregnancy and lactation. Female pregnant Wistar rats were randomly divided into five groups: group D pregnant rats were fed with low dose of lead (50ppm); group E pregnant rats were fed with high dose of lead (200ppm); group B rats in lactation were fed with low dose of lead (50ppm); group C rats in lactation were fed with high dose of lead (200ppm); group A was the control group. The newborn rat’s incisor eruption rate was then measured.

Results
Our data showed that the newborn which were exposed to lead during lactation stage had reduced eruption rates of incisors, particularly in high dose.In histological observation, the newborn which were exposed to lead during lactation stage had thiner odontblasts layer; the newborn which were exposed to lead during pregnant stage had irregular odontblasts layer.

Conclusion
In conclusion, the data had suggested the newborns exposed to lead during lactation had reduced eruption rate and were more sensitive to lead exposure.

並列關鍵字

Lead ； tooth ； rats ； eruption rates

參考文獻

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