Effect of Holarrhena pubescens on a Model Tapeworm of Poultry-alterations in Nitric Oxide Synthase
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Published on: December 4, 2013
Rachita Saha1, Manjil Gupta1,2, Subrata Saha1
1Parasitology Laboratory, Department of Zoology, Cooch Behar Panchanan Barma University, Cooch Behar, West Bengal, India.
Background:
Tapeworms of the genus Raillietina are widespread intestinal parasites of poultry, posing significant challenges to livestock productivity. Increasing resistance to conventional anthelmintics has driven interest in plant-based alternatives. Nitric oxide (NO), produced by NO synthase (NOS), is a key regulator of neuromuscular and cellular functions, yet its potential as a drug target in cestodes remains underexplored.
Aim:
This study aimed to determine the histomorphological localization of neuronal NOS (NOS1) and inducible NOS (NOS2) immunoreactive structures in Raillietina spp., and to evaluate their modulation following treatment with extracts of Holarrhena pubescens.
Materials And Methods:
Raillietina spp. were treated with 20 mg/mL phosphate-buffered saline of the ethanolic extract of bark of H. pubescens and its ethyl acetate fraction. NOS activity was localized using NADPH-diaphorase histochemistry in whole mounts and cryosections. Immunofluorescence was performed using rabbit polyclonal antibodies against NOS1 and NOS2. Biochemical assays included estimation of NOS activity via citrulline formation and NO release as nitrite using the Griess reaction.
Results:
Histochemical analysis revealed widespread NOS activity in the tegument, musculature, and parenchyma. Immunofluorescence showed distinct localization patterns, with NOS1-like immunoreactivity being broadly distributed, while NOS2-like immunoreactivity was predominantly confined to the tegument. Treatment with H. pubescens extracts was associated with significantly enhanced NOS expression and NO release.
Conclusion:
This study provides the first immunofluorescent evidence of NOS1-like and NOS2-like immunoreactivity in Raillietina spp. and demonstrates their modulation linked to treatment with extracts of H. pubescens. These findings highlight the possibility of NOS as a potential target for the anthelmintic effects of the extracts. However, these findings remain preliminary given the inherent limitations of an in vitro model, the absence of functional NOS inhibition assays, and the reliance on heterologous mammalian antibodies without isoform-specific molecular validation in Raillietina spp.
