Histological and Ultrastructural Changes of Cardiomyocytes in Experimental Rats with Tail Thrombosis following Subplantar Application of Carrageenin

Objective: To describe histological and ultrastructural changes of cardiomyocytes in experimental rats following subplantar administration of carrageenin. Material and Methods: In adult rats, an acute inflammatory reaction was induced by subplantar injection of 0.1 ml of 1% sterile carrageenin solution. In a total of 10 rats, which developed gangrene of tails in 5- to 12-cm-long segments, were killed and their internal organs fixed in 10% formaldehyde solution and subsequently processed for paraffin embedding. Later, blocks of the ventricular heart tissue were refixed and reprocessed for Araldite embedding and ultrastructure observation. Similarly, the cardiac muscle of control, carrageenin-injected rats which did not develop vascular thrombosis was processed. Results: The cardiomyocytes of rats injected with carrageenin showed focal dystrophic alterations, enlarged mitochondria with densely packed concentrically oriented cristae, and many dense and irregularly shaped deposits with microgranular helicoid organization. Normal cardiomyocytes were observed in control rats. Complicating thrombosis of tail blood vessels leading to extensive tail necroses were also histologically confirmed. Conclusion: These findings demonstrate specific pathogenic effect in the cardiovascular system of the carrageenin-treated rats.