Células germinativas e células de Leydig em modelo de dano testicular no rato
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Data
2018-02-26
Autores
Lima, Thania Rios Rossi
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Universidade Estadual Paulista (Unesp)
Resumo
Evidências epidemiológicas sugerem a influência de xenobióticos no aumento da incidência de desordens do trato reprodutor masculino como criptorquidia, hipospadia, baixa qualidade do sêmen e tumores testiculares. Dentre elas, a criptorquidia é a anomalia congênita mais comum em meninos e é um fator de risco para o desenvolvimento de infertilidade e tumor testicular. O objetivo deste estudo foi avaliar morfologicamente os testículos de ratos criptorquídicos expostos in utero e no período pós-natal à acrilamida (AA) ou ao di-n-butil-ftalato (DBP). Durante a gestação e a lactação, as ratas prenhes foram expostas a AA 10 mg/kg/dia ou DBP 500 mg/kg/dia por gavagem e dieta, respectivamente. Após o desmame (dia pós-natal; DPN 21), a prole masculina foi submetida a cirurgia de criptorquidia (CPT), revertida por orquidopexia (R) após três semanas, continuamente expostos aos xenobióticos por dieta até a eutanásia quando com 16, 31 ou 58 semanas de idade. Os testículos foram avaliados por sistema de classificação de danos histológicos, imunohistoquímica para os antígenos tirosina quinase Kit (c-Kit) e fosfatase alcalina placentária (PLAP), e análise morfométrica das células de Leydig. Os resultados mostraram redução do peso corpóreo apenas no grupo AA/CPT-R na 16ª semana, mas ambos os grupos tratados apresentaram uma redução progressiva no peso testicular absoluto e no volume testicular em todos os momentos de estudo. As alterações histológicas apresentaram maior severidade nos grupos AA/CPT-R e DBP/CPT-R. Na 31ª e 58ª semanas, em animais do grupo AA/CPT-R foi encontrada predominância significativa de túbulos com células marcadas com c-Kit associada à redução da imunorreatividade para PLAP; o grupo DBP/CPT-R apresentou redução da imunorreatividade para PLAP na 58ª semana. Na 16ª semana, o volume total ocupado pelas células de Leydig apresentou-se diminuído em ambos os grupos expostos às substâncias químicas; o índice Leydigossomático (volume relacionado a massa corporal) apresentou-se diminuído no grupo DBP/CPT-R. O número de células de Leydig/ml apresentou-se aumentado no grupo DBP/CPT-R na 16ª semana, e também nos grupos AA/CPT-R e DBP/CPT-R nas 31ª e 58ª semanas. Os métodos de avaliação testicular adotados são individualmente capazes de detectar o dano testicular e, particularmente, o comprometimento da espermatogênese. Este modelo experimental mostrou-se útil para avaliar alterações testiculares induzidas por xenobióticos.
Epidemiological evidence suggests the influence of xenobiotics on the increased incidence of male reproductive tract disorders such as cryptorchidism, hypospadias, poor semen quality and testicular tumors. Among them, cryptorchidism is the most common congenital anomaly in boys and is a risk factor for the development of infertility and testicular tumor. The aim of this study was to evaluate morphologically the testes of cryptorchid rats exposed in utero and postnatally to the acrylamide (AA) or di-n-butyl-phthalate (DBP). During gestation and lacta-tion, dams were exposed to AA 10 mg/kg/day or DBP 500 mg/kg/day by gavage and diet, respectively. After weaning (postnatal day; PND 21), male pups were surgically made cryp-torchid (CPT), reverted by orchiopexy (R) three weeks later, continuously exposed to the xe-nobiotics by diet until euthanasia when 16-, 31- or 58-week old. The testes were evaluated by histological damage classification system, immunohistochemical for the antigens tyrosine kinase Kit (c-Kit) and placental alkaline phosphatase (PLAP), and morphometric analysis of Leydig cells. The results showed a decrease in the body weight only in the AA/CPT-R group at 16th week, but both treated groups presented a progressive decrease in the absolute testicu-lar weight and testicular volume in all the moments of study. The histological alterations pre-sented greater severity in the AA/CPT-R and DBP/CPT-R groups. A significant predomi-nance of tubules with c-Kit strongly labeled cells was found in the AA/CPT-R group at the 31st and 58th weeks after birth, associated to reduction of the immunoreactivity for PLAP; DBP/CPT-R group presented decreased immunoreactivity for PLAP at the 58th week. The total volume occupied by Leydig cells decreased in both chemically-exposed groups at the 16th week; Leydig-somatic index (volume related to the body mass) was significantly de-creased in the DBP/CPT-R group. The number of Leydig cells/ml was increased in the DBP/CPT-R group at the 16th week, and in the AA/CPT-R and DBP/CPT-R groups at the 31st and 58th weeks. The methods of testicular evaluation adopted are individually able to detect testicular damage and, particularly, the compromising of the spermatogenesis. This experi-mental model showed to be useful to evaluate testicular alterations induced by xenobiotics.
Epidemiological evidence suggests the influence of xenobiotics on the increased incidence of male reproductive tract disorders such as cryptorchidism, hypospadias, poor semen quality and testicular tumors. Among them, cryptorchidism is the most common congenital anomaly in boys and is a risk factor for the development of infertility and testicular tumor. The aim of this study was to evaluate morphologically the testes of cryptorchid rats exposed in utero and postnatally to the acrylamide (AA) or di-n-butyl-phthalate (DBP). During gestation and lacta-tion, dams were exposed to AA 10 mg/kg/day or DBP 500 mg/kg/day by gavage and diet, respectively. After weaning (postnatal day; PND 21), male pups were surgically made cryp-torchid (CPT), reverted by orchiopexy (R) three weeks later, continuously exposed to the xe-nobiotics by diet until euthanasia when 16-, 31- or 58-week old. The testes were evaluated by histological damage classification system, immunohistochemical for the antigens tyrosine kinase Kit (c-Kit) and placental alkaline phosphatase (PLAP), and morphometric analysis of Leydig cells. The results showed a decrease in the body weight only in the AA/CPT-R group at 16th week, but both treated groups presented a progressive decrease in the absolute testicu-lar weight and testicular volume in all the moments of study. The histological alterations pre-sented greater severity in the AA/CPT-R and DBP/CPT-R groups. A significant predomi-nance of tubules with c-Kit strongly labeled cells was found in the AA/CPT-R group at the 31st and 58th weeks after birth, associated to reduction of the immunoreactivity for PLAP; DBP/CPT-R group presented decreased immunoreactivity for PLAP at the 58th week. The total volume occupied by Leydig cells decreased in both chemically-exposed groups at the 16th week; Leydig-somatic index (volume related to the body mass) was significantly de-creased in the DBP/CPT-R group. The number of Leydig cells/ml was increased in the DBP/CPT-R group at the 16th week, and in the AA/CPT-R and DBP/CPT-R groups at the 31st and 58th weeks. The methods of testicular evaluation adopted are individually able to detect testicular damage and, particularly, the compromising of the spermatogenesis. This experi-mental model showed to be useful to evaluate testicular alterations induced by xenobiotics.
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Palavras-chave
rato, testículo, criptorquidia, acrilamida, di-n-butil-ftalato