Role of heme oxygenase-1, cytokines, and vascular endothelial growth factor in murine Schistosoma mansoni

OBJECTIVES: Among tropical diseases, schistosomiasis caused by Schistosoma mansoni is the second major cause of morbidity and mortality worldwide. Inflammation was considered as an adverse event that contributes to the pathology associated with schistosomiasis. Heme oxygenase-1 (HO-1) and vascular endothelial growth factor (VEGF) have been implicated in the process of angiogenesis. The current study aimed to evaluate the effect of S. mansoni infection on HO-1 gene expression, IL-4, IL-12, and VEGF to address the role of these factors in the pathogenesis of schistosomiasis. METHODS: Thirty mice divided equally into three groups comprised a non-infected control group and two S. mansoni-infected groups. Infected animals were studied at 8 and 12 weeks post-infection. Serum IL-4, IL-12, and VEGF were measured. HO-1 mRNA was detected by RT-PCR of liver homogenates and HO activity was assessed as percentage of carboxy hemoglobin. RESULTS: S. mansoni-infected mice showed a progressive increase in serum IL-4 and VEGF and decrease in IL-12 levels. In addition, HO-1 expression and activity were increased in infected mice compared to control group with the maximum increase at egg deposition stage. CONCLUSION: Our results suggested that the body response to acute stage of S. mansoni infection by elevating the expression of the stress gene HO-1 and that VEGF may serve as a new indicator of progression of S. mansoni associated angiogenesis which regulates granuloma and/or fibrosis development in the liver of infected mice. Understanding the role of HO-1 and VEGF in pathogenesis of S. mansoni may provide a new pharmacological target.