Effects of Manganese Exposure on the Testis Function and Serum Prolactin Concentration in Rat

망간 노출이 흰쥐의 정소기능과 혈청 프로락틴 농도에 미치는 영향

  • Lee, Chae-Kwan (Institute of Environmental and Occupational Medicine & Department of Occupational and Environmental Medicine, Busan Paik Hospital, Inje University)
  • 이채관 (인제대학교 환경.산업의학연구소, 부산백병원 산업의학과)
  • Published : 2009.12.31

Abstract

This study aimed to examine the testis toxicities of metal compound, manganese (Mn), which may be generated as mist or fume in the industrial sites. As well as serum prolactin (PRL) concentration was analyzed because Mn accumulation in basal ganglia up-regulates serum PRL and hyperprolactinemia consecutively induces the testis toxicity. Male F344 rats were divided into the 4 groups (2 controls and 2 Mn treated groups, n=10) on the basis of the test condition (inhalation, Mn $1.5mg/m^3$ or not) and treatment period (for 4-weeks and 13-weeks). The treatment time was 6 hr. a day, 5 days a week for the whole body. Basic tests including changes in body weight, feed rate were observed. Blood and testis Mn concentration, and testis toxicity test such as the number and deformity test of sperm were also observed. Serum PRL level was analyzed by ELISA to certify the relationship between the Mn induced increase of the serum PRL level and sperm production. Blood and testis Mn concentrations were significantly and dose-dependently increased. Sperm count was decreased in Mn-treatment groups than control in a treatment time dependent manner. Morphological analysis of cauda epidydimal sperm showed that the frequencies of morphologically abnormal sperms such as bent tail and small head were increased in the both Mn-treatment groups than control. A significant increase in serum PRL levels was found in response to Mn treatment but it was not hyperprolactinemia range. These results suggest that treatment of Mn up-regulates the serum PRL concentration and induces the testis toxicity. The No Aversed Effect Level (NOAEL) of inhaled Mn on the male rat testis may be under the $1.5mg/m^3$.

망간은 정소 독성을 나타내며, 뇌기저핵에 작용하여 혈청 프로락틴의 농도를 증가시킨다. 그리고 혈청 프로락틴 농도 상승에 의한 과프로락틴혈증(hyperprolactinemia)은 정소의 정자 생성을 억제한다. 본 연구에서는 망간의 전신 노출이 흰쥐 정소의 정자 생산과 혈청 프로락틴 농도에 미치는 영향을 조사하기 위하여 실험동물을 대조군 $(0.0mg/m^3)$과 망간 노출군 (Mn $1.5mg/m^3$)으로 나누고, 노출군은 다시 노출 기간에 따라 4주와 13주 노출군 등 4군으로 분류하였다(n=10). 노출 기간에 따라 실험동물의 체중 변화와 사료 섭취량 등 일반적 소견 관찰, 혈액과 정소의 망간 농도, 정자의 수와 기형 등을 관찰하였다. 그리고 망간 노출에 따른 혈청 프로락틴 농도를 조사하여 망간 노출 조건에 따른 혈청 프로락틴 농도 변화 및 정소 독성을 조사하였다. 망간 노출 4주 및 13주군에서 노출기간에 따라 혈액 및 정소의 망간 농도가 유의하게 증가되었다. 대조군에 비하여 망간 노출군에서 노출기간에 따라 정자의 수가 감소되었으며, small head와 bent tail 등 기형 정자의 빈도는 증가하였다. 혈청 프로락틴의 농도는 망간 투여군에서 대조군에 비하여 유의하게 증가하였다. 그러나 실험동물의 체중 변화 및 사료 섭취량은 실험군간에 차이가 없었다. 이러한 결과들로 보아 $1.5mg/m^3$ 농도의 아만성 망간 노출은 흰쥐의 혈청 프로락틴 농도를 증가시키고, 정소 독성의 원인으로 추정된다. 그리고 전신 노출에 의한 망간의 흰쥐 정소 독성의 무유해영향농도(NOAEL)는 $1.5mg/m^3$ 이하로 예측된다.

Keywords

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