Abstract

To study the pathological and possible molecular changes of small intestine during prohemistomumiasis, a total of 30 BALB/c mice were experimentally infected orally with 150 encysted metacerceriae / mouse of Prohemistomum vivax. Groups of 3 mice, each, were dissected at 6 and 12 h. and subsequently on daily basis up to 7 days post-infection (p.i.) as well as non-infected controls. Tissues of jejunum/upper intestine were immediately removed, fixed and prepared for histopathological investigation. On the other hand, tissue specimens from the above mentioned area were collected, RNAs were extracted and semi-quantitative reverse transcription-polymerase chain reaction was performed to analyze the expression of the multifunctional cytokine transforming growth factor-beta (TGF-β). Light microscopic examination showed compression and sometimes erosions of intestinal epithelial lining especially at the site of parasite attachment. The villi underwent deformation in the form of shortening, blunting and fission, which progressed with the infection time. Some villi were totally eradicated at the parasite localization. Hypertrophy of crypts was parallelly observed. In addition, inflammatory cell infiltration was recorded in the lamina propria of the parasitized intestine. These changes reached its peak value at the end of the experiment. At the same time, the molecular outcome was in accordance with the pathological findings. The expression of TGF-β was normal at baseline and increased progressively along the infection time compared with that in non-infected control. These findings strongly support a role for TGF-β during P. vivax infection. The recorded results were discussed in the light of the available literature.

Key words: Trematode parasite, Prohemistomum vivax, transforming growth factor-ß, RT-PCR.