RESUMO
To investigate the effects of Hericium erinaceus polysaccharide (HEP) on immunity in Muscovy duck reovirus (MDRV)-infected ducklings and explore its mechanism of action, an MDRV contact-infection model was established. Then, we investigated the influence of HEP on morphology of main immune organs in MDRV-infected ducklings by HE staining, while antioxidant capacity (T-AOC, MDA), serum protein levels (TP, ALB, GLO), complement levels (C3, C4) and antibody levels (IgA, IgM, IgG) were detected. Apoptotic indexes (apoptosisi rate and FAS-L) were also quantified by TUNEL method and immunohistochemical staining. Meanwhile, FADD and CytC (apoptosis-related genes), were tested by quantitative RT-PCR. Results showed that HEP could reduce the injuries of immune organs caused by MDRV. Additionally, HEP markedly diminished MDA (p < 0.01), while significantly increased T-AOC, TP, ALB, GLO, C3, C4, IgA, IgM and IgG (p < 0.01 or p < 0.05). Then, HEP shifted apoptosis time to an early MDRV-infected stage and reduced apoptosis at later MDRV-infected stage. This was associated with changes of FADD and CytC. Collectively, our data suggested that HEP could reduce the immunesuppression by many ways, such as decreasing organs' injuries, improving antioxidant capacity, serum proteins levels, antibody levels and complement levels, while diminish the apoptosis by lowering the FADD and CytC.