Enalapril alters the formation of the collagen matrix in spontaneously hypertensive rats

OBJECTIVE: To assess the effect of the inhibition of the angiotensin-converting enzyme on the collagen matrix (CM) of the heart of newborn spontaneously hypertensive rats (SHR) during embryonic development. METHODS: The study comprised the 2 following groups of SHR (n=5 each): treated group - rats conceived from SHR females treated with enalapril maleate (15 mg. kg-1.day-1) during gestation; and nontreated group - offspring of nontreated females. The newborns were euthanized within the first 24 hours after birth and their hearts were removed and processed for histological study. Three fields per animal were considered for computer-assisted digital analysis and determination of the volume densities (Vv) of the nuclei and CM. The images were segmented with the aid of Image Pro Plus® 4.5.029 software (Media Cybernetics). RESULTS: No difference was observed between the treated and nontreated groups in regard to body mass, cardiac mass, and the relation between cardiac and body mass. A significant reduction in the Vv[matrix] and a concomitant increase in the Vv[nuclei] were observed in the treated group as compared with those in the nontreated group. CONCLUSION: The treatment with enalapril of hypertensive rats during pregnancy alters the collagen content and structure of the myocardium of newborns.

Estrategias reproductivas de lagartos del género tupinambis en distintos contextos ecológicos de la Provincia de Córdoba. Reproductive strategies of lizards of genus tupinambis in different ecological contexts of the Cordoba province.

Los caracteres de historia de vida son sensibles a la variación histórica o actual de los factores ambientales. Estudiar dicha variabilidad mediante la realización de estudios comparativos permite obtener evidencias sobre las causas de la evolución de ciertos caracteres. Los lagartos son excelentes modelos para el estudio de selección sexual y evolución del comportamiento social y reproductivo debido a que su relativa baja dispersión podría tener consecuencias evolutivas profundas en el desarrollo de distintas estrategias, ya que las poblaciones, al encontrarse más aisladas, podrían verse influenciadas por las fuerzas selectivas locales, mostrando una alta heterogeneidad espacial y temporal. Por eso nos propusimos realizar este trabajo para evaluar si existen diferentes estrategias reproductivas en los lagartos del género Tupinambis en distintos contextos ecológicos de la provincia de Córdoba. Para ello analizaremos distintas características de la historia de vida en poblaciones de estas especies tales como estructura de tamaño, sexo operativo, frecuencia reproductiva, tamaño de camada, condición corporal reproductiva, tamaño de madurez sexual, características espermáticas, elección de sitios de nidificación, etc. Además analizaremos la estructura genética de las poblaciones para inferir procesos demográficos históricos y patrones actuales de flujo génico y conectividad. The life history traits are sensitive to historical or current variation of environmental factors. Studying this variability by performing comparative studies allows obtaining evidence on the causes of the evolution of certain characters. Lizards are excellent models for studying sexual selection and evolution of social and reproductive behavior because their relatively low dispersal capabilities could have profound evolutionary consequences in the development of different strategies, since isolated populations may be stronger influenced by local selective forces, showing a high spatial and temporal heterogeneity. We decided to perform this study to assess whether there are different reproductive strategies in lizards of the genus Tupinambis in different ecological contexts of the Cordoba province. We will analyze different life history traits in populations of these species such as size structure, operational sex ratio, reproductive frequency, litter size, body condition, size at sexual maturity, sperm characteristics, choice of nesting sites, etc.. We also analyzed the genetic structure of populations to infer historical demographic processes and current patterns of gene flow and connectivity.