Abstract The genus Rhinella is one of the most diverse groups of bufonid toads, currently composed by 93 valid species and naturally distributed throughout different Neotropical ecoregions. Here, we analyze nine Brazilian populations of toads representing species of the Rhinella margaritifera and Rhinella marina groups. These new data include the first description of the R. hoogmoedi and R. proboscidae karyotypes, as well as other taxonomically unresolved forms. Chromosomal analysis of the populations revealed pronounced chromosomal uniformity (2n=22), including the diploid number and chromosomal morphology. Three different NOR-bearing chromosomes were identified: in the subterminal region of pair 10q in R. hoogmoedi, Rhinella sp. 1 and Rhinella sp. 2, in subterminal region of 7p in R. proboscidae and Rhinella cf. margaritifera while in R. henseli and R. icterica was detected in interstitial region of 7p. Karyotypic uniformity of the genus permits the inference of interspecific chromosome homologies and evolutionary changes in the NOR-bearing chromosome may represent an informative character in species group level. The review of the cytogenetic data of the Rhinella species together with the new karyotypes reported here contributes to the understanding of the chromosomal evolution of these toads, which karyotypes are highly conserved despite the ample distribution of many forms.

O propósito deste estudo foi avaliar o potencial proliferativo celular das lesões de líquen plano bucal (LPB) de pacientes sem vírus da hepatite C (VHC) por meio do método AgNOR, comparando-o ao potencial proliferativo celular da mucosa bucal normal de portadores de VHC, tratados ou não com interferon e ribavirina. Um estudo transversal foi realizado para investigar 4 grupos: 10 pacientes VHC+ sem sinais clínicos de LPB que nunca haviam sido tratados para a infecção por VHC - Grupo 1; 10 pacientes VHC+ que estavam sob tratamento com interferon e ribavirina - Grupo 2; 15 pacientes com LPB reticular histopatologicamente confirmado, sem VHC - Grupo 3; e 15 doadores de sangue sem infecção por VHC e sem sinais clínicos de LPB (Grupo 4 - Grupo de Controle). O material celular de todos os grupos foi coletado pela técnica da citologia em base líquida. Então, o material sedimentado de cada paciente foi submetido ao método da impregnação das regiões organizadoras nucleolares pela prata (AgNOR). A contagem das NORs foi realizada em 100 núcleos celulares epiteliais por paciente por meio do programa Image Tool(r). O teste Tukey HSD foi utilizado para comparar o valor médio de NORs entre os grupos e mostrou que a mucosa bucal dos pacientes VHC+ previamente tratados com fármacos anti-VHC (Grupo 2) apresentou maior número médio de NORs por núcleo em relação aos outros (p<0,05). O tratamento anti-VHC pode estar relacionado ao aumento da atividade proliferativa celular da mucosa bucal, aventando uma possível relação entre LPB e pacientes VHC+ tratados com interferon e ribavirina.

The objective of this study was to evaluate the cellular proliferative potential of oral lichen planus (OLP) lesions from patients without hepatitis C virus (HCV) by means of AgNOR method, as well as the cellular proliferative potential of the normal oral mucosa from patients with HCV, treated or untreated by interferon and ribavirin. A cross-sectional study was developed to investigate four groups: 10 HCV+ patients without clinical signs of OLP who had never been treated for HCV infection - Group 1; 10 HCV+ patients that were under interferon and ribavirin treatment - Group 2; 15 patients with reticular OLP lesions histopathologically confirmed, without HCV - Group 3; and 15 blood donors without HCV infection and no clinical signs of OLP GROUP 4 Control Group. The cytological material of all groups was collected by the liquid-based cytology technique. Then, the sedimented material from each patient was filled with the Nucleolar Organizer Regions impregnation by silver method (AgNOR). The count of NORs was performed on 100 epithelial cell nuclei per patient using the Image Tool(tm) software. The Tukey HSD test was used to compare the median value of NORs among the groups and showed that the oral mucosa of HCV+ patients previously treated with anti-HCV drugs (GROUP 2), presented a higher average number of NORs in relation to others (p<0.05). The anti-HCV treatment may be related to increased cell proliferation of oral mucosa, indicating a possible relationship between OLP and HCV+ patients treated with interferon and ribavirin.