Contratilidade gastroduodenal em ratos parasitados por Strongyloides venezuelensis : aspectos imunológicos e fisiopatológicos

Abstract

Strongyloidiasis is a neglected tropical disease caused by Strongyloides stercoralis in humans. While parasite involvement in gastrointestinal (GI) motor disturbances has been described, the relationship between parasite burden, citokines and gastrointestinal contractility still remains unclear. The aim was correlated, by using a biomagnetic technique in rats, gastrointestinal contractility and cytokine levels in response to infection with different loads of S. venezuelensis. Magnetic marker was previously implanted in the duodenum of Wistar male rats for contractility parameters evaluation (frequency and amplitude gastric and duodenal). Experimental infections were induced by 400, 2000 and 10000 larvae of S. venezuelensis. The concentrations of TNF-α and IL-13 were determined by ELISA on gut tissue. Data were analyzed by ANOVA followed by Tukey test (p <0.05). Gastric frequency of control animals was 4.2 cycles per minute (cpm). Infection with 400 larvae of S. venezuelensis presented gastric frequencies increased in 9 and 12 dpi. Tachygastry was observed in 3, 9, 12, 15 and 24 dpi. Gastric frequency was not modified in groups infected with 2000 and 10000 larvae. A frequency of 34.03 cpm was recorded in the duodenum of control rats. On 9 and 12 dpi, the group infected with 400 larvae showed increased intestinal frequency. This parameter has not been altered after infection with 2000 and 10000 larvae. In the group 400L3 there were no significant changes in the amplitude of gastric contraction, except for a decrease in 21 dpi. In groups 2000 and 10000 were large fluctuations of this parameter. In the intestine, infection with 400 larvae caused significant variations until 21 dpi. Animals infected with 10000 larvae showed amplitude variations up to 21 dpi and 24 dpi. TNF-α and IL-13 levels in the intestinal homogenate showed peak at 15 dpi in the group 400. After infection with 2000 and 10000 larvae, TNF-α and IL-13 levels were reduced at 9 dpi with peak at 15 dpi. The implementation of an experimental model to evaluate the duodenum in vivo contractility in rats by using a biomagnetic technique was successful. The contractile activity differed between the different loads of S. venezuelensis, with major changes observed in the group 400. There was no direct relationship between IL-13 and NF-α peak and an increased gastric and/or intestinal contractility.