title: Chronic Intake of Green Propolis Negatively Affecting the Rat Testis.
abstract: BACKGROUND
  Human and animal evidence suggests that environmental toxicants may have an adverse impact on male reproductive health, reducing the population's reproductive output. Owing to the renewed attraction for natural products, some of them constitute effective alternatives to mitigate these effects. Propolis is a candidate for this use because of its intrinsic properties. In many situations, it improved the testicular damage and alleviated the toxic effects induced by environmental contaminant exposure.
  
  
  OBJECTIVE
  The aim of this study was to investigate possible alterations of testicular parameters and certify if its use is really advantageous to the testis, since this could affect rat reproductive function.
  
  
  METHODS
  Forty-eight adult male Wistar rats were divided into four groups (Co = control, T1 = 3 mg propolis/kg/day, T2 = 6 mg/kg/day, T3 = 10 mg/kg/day) and were exposed during 56 days. The testes were assessed with morphometrical, stereological, and ultrastructural analyses. Cell proliferation and death were diagnosed, respectively, by immunocytochemistry. Connexin 43 (Cx43) and N-cadherin transcript levels were determined by reverse transcription-polymerase chain reaction.
  
  
  RESULTS
  Increased cell proliferation and Leydig cell volume were observed in T2, and in contrast,Cx43upregulation and cell death were observed in T3. Both T2 and T3 showed ultrastructural abnormalities in testicular parenchyma.
  
  
  CONCLUSIONS
  We recommend a cautious intake of propolis to avoid deleterious effects.
  
  
  CONCLUSIONS
  Chronic intake of Brazilian green propolis induced N.-cadherin downregulation and decreased on seminiferous tubule volumeIncrease on connexin 43 expression and cell death and decrease in Leydig cell.(LC) number/testis with the concentration of 10 mg/kg/day were observedIncrease on cell proliferation, cytoplasmic proportion, and volume of LC with the concentration of 6 mg/kg/day was detectedThe presence of empty spaces between spermatids and malformed spermatozoa in the lumen of seminiferous tubule was showedThis male reproductive disruption can be linked to phenolic compounds present in Brazilian green propolis.Abbreviation Used: AEC: 3-amino-9-ethylcarbazole; AJ: Adherens junction; AME: Aromadendrin-40-methyl ether; CAPE: Caffeic acid phenethyl ester; Co: Control group;C×43: Connexin 43; DAB: Diaminobenzidine; dNTP: Deoxyribonucleotide phosphate; DSP: Daily sperm production; FA: Ferulic acid; FSH: Follicle-stimulating hormone; GJ: Gap junction; GJIC: Gap junction intercellular communication; HPLC: High-performance liquid chromatography; LC: Leydig cell; LH: Luteinizing hormone;N-cad: N-cadherin; PCNA: Proliferating cell nuclear antigen; PCR: Polymerase chain reaction; RT-PCR: Reverse transcription-polymerase chain reaction; SDM: Standard deviation of mean; T1: Group exposed to 3 mg of propolis/kg/day; T2: Group exposed to 6 mg of propolis/kg/day; T3: Group exposed to 10 mg of propolis/kg/day; TUNEL: Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; WB-ras 2 cells: Ras-transformed rat liver epithelial cell line.
authors.affiliation: Reproductive Biology Laboratory, Department of Structural and Functional Biology, Biology Institute, State University of Campinas - UNICAMP, Campinas, Brazil.
authors.forename: Grasiela Dias de Campos
authors.initials: GD
authors.lastname: Severi-Aguiar
authors.affiliation: Heath Sciences Nucleus, Hermínio Ometto Univerity Center, UNIARARAS, Araras, São Paulo, Brazil.
authors.forename: Suellen Josine
authors.initials: SJ
authors.lastname: Pinto
authors.affiliation: Reproductive Biology Laboratory, Department of Structural and Functional Biology, Biology Institute, State University of Campinas - UNICAMP, Campinas, Brazil.
authors.forename: Cristina
authors.initials: C
authors.lastname: Capucho
authors.affiliation: Graduate Program in Biomedical Sciences, Hermínio Ometto University Center, UNIARARAS, Araras, São Paulo, Brazil.
authors.forename: Camila Andrea
authors.initials: CA
authors.lastname: Oliveira
authors.affiliation: Reproductive Biology Laboratory, Department of Structural and Functional Biology, Biology Institute, State University of Campinas - UNICAMP, Campinas, Brazil.
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: Diamante
authors.affiliation: Heath Sciences Nucleus, Hermínio Ometto Univerity Center, UNIARARAS, Araras, São Paulo, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Barbieri
authors.affiliation: Department of Biological Sciences, State University of Paraná (UNESPAR), Paranaguá, Paraná, Brazil.
authors.forename: Fabrícia Souza
authors.initials: FS
authors.lastname: Predes
authors.affiliation: Reproductive Biology Laboratory, Department of Structural and Functional Biology, Biology Institute, State University of Campinas - UNICAMP, Campinas, Brazil.
authors.forename: Heidi
authors.initials: H
authors.lastname: Dolder
keywords: Cell death and proliferation; N-cadherin; connexin 43; morphometry; stereology; ultrastructure