Schistosoma mansoni induce granulomatous inflammation and lesion to the enteric nervous system in mouse colon.

Schistosomiasis mansoni is a major health problem, mainly occurring in developing countries. A large proportion of infected individuals suffer from motility related gastrointestinal problems. In the present study the granulomatous inflammation induced by eggs deposition in the colon wall and the lesion to the enteric nervous system was investigated. Mice infected with S. mansoni 4-12 weeks prior to the experiment, and uninfected control mice were studied. The colon showed both a diffuse mucosal, submucosal and muscularies inflammation as well as a granulomatous reaction. The diffuse mucosal inflammation caused a prominent increase in the thickness of the mucosa. A significant increase of thickness of mascularis at 12 weeks of infection was noted. An increase of the number of entroendocrine cell was also noted at the acute phase. In addition, the enteric nervous tissue, submucous neurons and myenteric plexus, become inflamed, disturbed and destroyed by granulomas. Further more, ganglia situated within or near granulomas showed ganglionitis, necrosis of neurons as well as infiltration by eosinophils, neutrophils, plasma cells and macrophages. The myenteric plexus was the most damaged. We conclude that diffuse inflammation and lesion to the enteric nervous system may alter the regulatory functions of the enteric nervous system and the enteroendocrine cells and play an important role in the pathogenesis seen in Schistosomiasis symptoms.