Atrioventricular valvular angiectasis in Sprague-Dawley rats

Area of Science:

• Veterinary Pathology
• Cardiovascular Research
• Toxicology

Background:

• Subendothelial heart valve angiectasis is a known condition in various species.
• It has been documented in animals like cows, dogs, pigs, rats, mice, and in human fetuses and newborns.
• Differentiating spontaneous lesions from drug-induced effects is crucial in laboratory animal studies.

Purpose of the Study:

• To report the incidence and characteristics of spontaneous angiectasis in Sprague-Dawley rats.
• To identify the specific locations and prevalence of this vascular abnormality.
• To provide a reference for distinguishing these findings from chemically induced lesions.

Main Methods:

• Examination of 208 Sprague-Dawley rats aged 10 to 40 weeks.
• Histopathological analysis of heart valves using light microscopy.
• Documentation of the location, size, and morphology of observed angiectases.

Main Results:

• A high incidence of spontaneous angiectasis was observed in 62 out of 208 rats (29.8%).
• The condition predominantly affected the atrioventricular (AV) valves, particularly the septal cusp of the right AV valve near the AV ostium (57/62 cases).
• Angiectases were single or multiple, measured 40-300 micrometers, and were characterized as endothelium-lined, blood-filled dilatations.

Conclusions:

• Spontaneous valvular angiectasis occurs with significant frequency in Sprague-Dawley rats.
• The specific predilection for the right AV valve septal cusp is a key characteristic.
• These findings are essential for accurate interpretation of toxicological studies and drug safety evaluations in this animal model.