Pathogenic role of stress in myocardial injury experimentally induced by the pairing of Africanized bees in Wistar rats: lesion histomorphometry

Author(s)

Adriana Cristina Busollo

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 1998-06-22

Examining board members

Roberto Silva Costa; Joao Kazuyuki Kajiwara; Luiz Cesar Peres

• Advisor: Roberto Silva Costa

Abstract

The present study investigates the pathogenetic role of stress as a potentiating factor in the heart damage induced by experimental envenomation of Wistar rats with Afficanized bee venom, as determined by histomorphometry of the lesions. Histological analysis of the envenomed groups submitted or not to stress demonstrated a lesion similar to myocardial infarction involving small focal areas or large areas of the left ventricular myocardium. Loss of staining capacity of cardiac tissue was observed, at times with homogenization ofthe cytoplasm and of muscle fíbers, and disappearance of the nucleus accompained by an inflammatory infiltrate predominantly consisting of mononuclear leucocytes and few polymorphonuclear leucocytes permeating the damaged area. The focal points of necrosis showed characteristics of coagulative myocytolisys. Morphometric analysis showed that the envenomed groups submitted to stress presented a necrotic area signifícantly larger than those observed in the envenomed groups not submitted to stress. The present study shows that stress potentiates the cardiac damage induced by experimental envenomation of Wistar rats with Afficanized bee venom. The mechanism leading to this potentiation is discussed. (AU)