Oxytocin neuron activation by acute infusion of Montanoa genus plants in the Wistar rats / Activación de neuronas de oxitocina por la infusión aguda de plantas del género de Montanoa en la rata Wistar

In tradition al Mexican medicine, plants from the Montanoa genus, family Asteraceae ( Montanoa tomentosa , Montanoa grandiflora , and Montanoa frutescens ) have been used to induce labor owing to their uterotonic properties like those produced by oxytocin (OXT). However, w hether infusions of these plants can activate hypothalamic OXT - producing neurons is unknown. To test this possibility, five independent groups of Wistar rats (n=4) were included: intact, vehicle, and three groups that received 50 mg/kg p.o. of M. tomentosa , M. grandiflora , and M. frutescens infusions, respectively. Ninety min after treatment, the brains were obtained and processed using double - labeled immunohistochemistry for Fos protein and oxytocin (Fos/OXT - ir). Rats that received Montanoa infusions had s ignificantly greater number of Fos/OXT - ir cells in the paraventricular (PVN) and supraoptic (SON) nuclei, with respect to intact and vehicle groups. These findings demonstrate that Montanoa infusions activated OXT neurons, an effect that may be related to the reported pharmacological properties.

En la medicina tradicional mexicana, plantas del género Montanoa , familia Asteraceae ( Montanoa tomentosa , Montanoa grandiflora y Montanoa frutescens ), se han utilizado para inducir el parto debido a sus propiedades uterotónicas, aparentemente similares a las producidas por la hormona oxitocina (OXT). Sin embargo, se desconoce si las infusiones de estas plantas pueden activar neuronas hipotalámicas productoras de OXT. Para probar esta posibilidad, se incluyeron cinco grupos independientes (n=4): intacto, vehículo y tres grupos que recibieron 50 mg/kg p.o. de infusiones de M. tomentosa , M. grandiflora , y M. frute scens , respectivamente. Noventa minutos después del tratamiento, los cerebros fueron obtenidos y procesados por doble marcaje de inmunohistoquímica para la proteína Fos y oxitocina (Fos/OXT - ir). Las ratas que recibieron infusiones de Montanoa aumentaron si gnificativamente el número de células Fos/OXT - ir en los núcleos paraventricular (PVN) y supraóptico (SON), respecto a los grupos intacto y vehículo. Estos hallazgos demuestran que las infusiones de Montanoa activan neuronas de OXT, lo que podría estar rela cionado con sus propiedades farmacológicas

BrdU does not induce hepatocellular damage in experimental Wistar rats.

Bromodeoxyuridine (BrdU) is used in studies related to cell proliferation and neurogenesis. The multiple intraperitoneal injections of this molecule could favor liver function profile changes. In this study, we evaluate the systemic and hepatocellular impact of BrdU in male adult Wistar rats in 30 %-partial hepatectomy (PHx) model. The rats received BrdU 50 mg/Kg by intraperitoneal injection at 0.5, 1, 2, 3, 6, 9 and 16 days after 30 %-PH. The rats were distributed into four groups as follows, control, sham, PHx/BrdU(-) and PHx/BrdU(+). On day 16, we evaluated hepatocellular nuclei and analyzed histopathological features by haematoxylin-eosin stain and apoptotic profile was qualified by caspase-3 presence. The systemic effect was evaluated by liver markers such as alanine transferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (AP), bilirubin, total proteins and serum albumin content. The statistical analysis consisted of a student t-test and one-way ANOVA. BrdU did not induce apoptosis or hepatocellular damage in male rats. Multiple administrations of BrdU in male rats did not induce significant decrease body weight, but increased serum ALT and LDH levels were found. Our results show that the BrdU does not produce hepatocellular damage.

Long-term ovariectomy increases anxiety- and despair-like behaviors associated with lower Fos immunoreactivity in the lateral septal nucleus in rats.

In woman, surgical menopause is associated with anxiety and depression symptoms. Ovariectomy in rats has been proposed as an experimental model of surgical menopause, but its long-term effects on anxiety- and depression-like behaviors and relationship with cellular changes in specific brain structures are unknown. The effects of ovariectomy on anxiety- and despair-like behavior 1, 3, 6, 9, 12, and 15-weeks postovariectomy were evaluated. Fos-immunoreactivity was evaluated in the lateral septal nucleus (LSN). The effects were compared with rats in the proestrus-estrus and metestrus-diestrus phases of the ovarian cycle and with ovariectomized rats that received 17ß-estradiol (OVXE). Three weeks postovariectomy, the rats exhibited an increase in anxiety-like behavior compared with PE and OVXE groups. Decreases in the locomotor activity and time spent grooming and rearing were detected in all the ovariectomized rats. In the forced swim test, the rats exhibited an increase in immobility time 6-weeks postovariectomy compared with control groups. The Fos-immunoreactivity in the LSN was significantly lower in all groups of ovariectomized rats compared with control groups. These findings indicate that rats develop anxiety-like behavior 3-weeks postovariectomy. Six weeks postovariectomy, the rats also developed despair-like behavior, which was associated with a reduction of Fos immunoreactivity in the LSN. Long-term ovariectomy may be considered a useful tool for understanding the development of neurobiological changes associated with surgical menopause. This model may also be useful for evaluating potential anxiolytic and antidepressant effects of diverse substances to ameliorate typical emotional and affective disorders during surgical menopause in women.