RESUMO
The number of myenteric neurons may be reduced by topical serosal application of benzalkonium chloride (BAC). We studied the effects of ageing in the population of neurons that survive after the application of BAC. Ten treated and ten control animals were killed at intervals of 2, 6, 12 and 18 months after the surgery. We performed myenteric neurons counting in serially cut histological preparations of the descending colon. The control animals revealed a continuous loss of myenteric neurons number with increasing of age. Interestingly, contrary to control animals, the BAC-treated rats presented no neuron loss with ageing at any experimental time. The reasons for their survival with ageing could be related to a neuroplasticity phenomenon.
Assuntos
Envelhecimento , Compostos de Benzalcônio/farmacologia , Plexo Mientérico/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Animais , Contagem de Células , Colo Sigmoide/efeitos dos fármacos , Colo Sigmoide/inervação , Masculino , Plexo Mientérico/citologia , Ratos , Ratos WistarRESUMO
Four months of sigmoid colon intrinsic denervation of young male Wistar rats resulted in typical megacolon. Average 46.0% denervation of the Auerbach plexus was obtained by serosal application of benzalkonium chloride (0.2% v/v). Denervation was assessed by ganglion cell counts in a 480-nm extension of the treated segment. Increased thickness of the megacolon wall was due to muscle hypertrophy (+117.4%) and mucosal hyperplasia (+53.9%) as shown by morphometry. The potential usefulness of this experimental model is emphasized.