Condensed Fuzheng extract increases immune function in mice with cyclophosphamide‐induced immunosuppression

Baicalin attenuates PD-1/PD-L1 axis-induced immunosuppression in piglets challenged with Glaesserella parasuis by inhibiting the PI3K/Akt/mTOR and RAS/MEK/ERK signalling pathways

Infection of piglets with Glaesserella parasuis (G. parasuis) induces host immunosuppression. However, the mechanism underlying the immunosuppression of piglets remains unclear. Activation of the PD-1/PD-L1 axis has been shown to trigger host immunosuppression. Baicalin possesses anti-inflammatory and immunomodulatory functions. However, whether baicalin inhibits PD-1/PD-L1 activation and thus alleviates host immunosuppression has not been investigated. In this study, the effect of baicalin on the attenuation of piglet immunosuppression induced by G. parasuis was evaluated. Seventy piglets were randomly divided into the control group, infection group, levamisole group, BMS-1 group, 25 mg/kg baicalin group, 50 mg/kg baicalin group and 100 mg/kg baicalin group. Following pretreatment with levamisole, BMS-1 or baicalin, the piglets were challenged with 1 × 108 CFU of G. parasuis. Our results showed that baicalin, levamisole and BMS-1 modified routine blood indicators and biochemical parameters; downregulated IL-1β, IL-10, IL-18, TNF-α and IFN-γ mRNA expression; and upregulated IL-2 and IL-8 mRNA expression in blood. Baicalin, levamisole and BMS-1 increased the proportions of CD3+ T cells, CD3+CD4+ T cells, CD3+CD8+ T cells and CD3-CD21+ B cells in the splenocyte population, increased the proportions of CD3+ T cells, CD3+CD4+ T cells and CD3+CD8+ T cells in the blood, and inhibited PD-1/PD-L1 and TIM-3 activation. Baicalin, levamisole and BMS-1 reduced p-PI3K, p-Akt, and p-mTOR expression, the p-MEK1/2/MEK1/2 and p-ERK1/2/ERK1/2 ratios and increased RAS expression. Baicalin, levamisole and BMS-1 provided substantial protection against G. parasuis challenge and relieved tissue histopathological damage. Our findings might provide new strategies for controlling G. parasuis infection and other immunosuppressive diseases.

Preparation and adjuvanticity against PCV2 of Viola philippica polysaccharide loaded in Chitosan-Gold nanoparticle

The present Porcine circovirus type 2 virus (PCV2) vaccine adjuvants suffer from numerous limitations, such as adverse effects, deficient cell-mediated immune responses, and inadequate antibody production. In this study, we explored the potential of a novel nanoparticle (CS-Au NPs) based on gold nanoparticles (Au NPs) and chitosan (CS) that modified Viola philippica polysaccharide (VPP) as efficient adjuvants for PCV2 vaccine. The characterization demonstrated that CS-Au-VPP NPs had a mean particle size of 507.42 nm and a zeta potential value of -21.93 mV. CS-Au-VPP NPs also exhibited good dispersion and a stable structure, which did not alter the polysaccharide properties. Additionally, the CS-Au-VPP NPs showed easy absorption and utilization by the organism. To investigate their immune-enhancing potential, mice were immunized with a mixture of CS-Au-VPP NPs and PCV2 vaccine. The evaluation of relevant immunological indicators, including specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations, confirmed their immune-boosting effects. The in vivo experiments revealed that the medium-dose CS-Au-VPP NPs significantly elevated the levels of specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations in PCV2-immunized mice. These findings suggest that CS-Au-VPP NPs can serve as a promising vaccine adjuvant due to their stable structure and immunoenhancement capabilities.

Toxicity studies of condensed fuzheng extract in mice and rats

Nutritional supplements have been used to improve immune function. Condensed fuzheng extract (CFE) is a well-known traditional Chinese medicine (TCM) formula that is predominantly made from sheep placenta, Astragalus mongholicus Bunge, and Polygonatum kingianum Collett & Hemsl. However, the toxicological profile of CFE has not been determined. In this study, we investigated the acute (14 days) and sub-chronic (90 days) oral toxicities of CFE in mice and rats and the phytochemical composition of CFE.

Materials and methods

For the assessment of acute toxicity, 80 ICR mice of both sexes were randomly divided into four groups. Three groups were treated with 4500, 2250 and 1125 mg/kg/d bw CFE daily (n = 10/group per sex) for 14 days; a separate group was used as control. To test the sub-chronic toxicity, male and female Sprague Dawley rats were orally administered 8150, 4075 or 2037 mg/kg bw of CFE for 90 days; a control group was included. Hematological, biochemical, and histopathological markers were tested at the end of the experiment. The chemical composition of CFE was determined by UPLC-HRMS method.

Results

In both acute and sub-chronic toxicity studies, no mortalities, indications of abnormality, or treatment-related adverse effects were observed. The LD50 of CFE was higher than 4500 mg/kg. There were no significant changes in the hematological and biochemical data in the treatment group compared with the control group (p > 0.05). Histopathological analyses of the heart, liver, spleen, lungs, kidneys, thymus, testes (male rats) and ovaries (female rats) revealed no anatomical changes of each organ. Phytochemical analysis of CFE revealed the presence of flavonoids (highest abundance), phenols and alkaloids. In conclusion, our results showed that CFE is a safe and non-toxic formula. We also reported phytochemicals in CFE that may possess important pharmacological effects.