Bio-mineralization has emerged as a promising strategy to enhance vaccine immunogenicity. This study optimized the calcium phosphate (CaP) mineralization process of foot-and-mouth disease virus-like particles (FMD VLPs) to achieve high mineralization efficiency and scalability. Key parameters, including concentrations of Ca²⁺, HPO₄^2-, NaCl, and VLPs, as well as stirring speed, were systematically optimized. Stability of the scaled-up reaction system and immunogenicity of the mineralized vaccine were evaluated. Optimal conditions [25.50 mmol/L Ca(NO₃)₂, 15 mmol/L Na₂HPO₄, 300 mmol/L NaCl, 0.75 mg/mL VLPs, and 1 500 r/min] yielded CaP-mineralized VLPs (VLPs-CaP) with high mineralization efficiency, uniform morphology, and a favorable particle size. Scaling up the reaction by 25 folds maintained consistent mineralization efficiency and particle characteristics. Immunization in mice demonstrated that VLPs-CaP induced higher titers of specific antibodies and neutralizing antibodies than unmineralized VLPs (P < 0.05). Higher IgG2a/IgG1 ratio and enhanced IFN-γ secretion (P < 0.05) further indicated robust cellular immune responses. We establish a stable and scalable protocol for VLPs-CaP, providing a theoretical and technical foundation for developing high-efficacy VLPs-CaP vaccines.
Vaccines, Virus-Like Particle/immunology* ; Immunogenicity, Vaccine ; Calcium Phosphates/chemistry* ; Foot-and-Mouth Disease Virus ; Biomineralization ; Particle Size ; Animals ; Mice ; Antibodies, Neutralizing/blood* ; Antibodies, Viral/blood* ; Immunity, Cellular

Vaccination is a crucial strategy for the prevention and control of infectious diseases. Virus-like particles (VLPs), composed of structural proteins, have garnered significant attention as a novel type of vaccine due to their excellent safety and immunogenicity. However, similar to most vaccine antigens, VLPs exhibit insufficient thermal stability, which not only restricts the widespread application of vaccines but also increases the risk of vaccine inactivation. This study aims to enhance the stability and shelf life of VLPs derived from type A foot-and-mouth disease virus (FMDV) by employing vacuum freeze-drying technology. The optimal lyoprotectant formulation was determined through single-factor and combinatorial screening. Subsequently, the correlation between the immunogenicity of the freeze-dried vaccine and the content of FMDV VLPs was evaluated via a mouse model. The stability of FMDV VLPs before and after freeze-drying was further assessed by storing them at 4, 25, and 37 ℃ for varying time periods. Results indicated that the lyoprotectant formulation No.1, composed of 7.5% trehalose, 0.1% Tween 80, 50 mmol/L glycine, 1% sodium glutamate, and 3% polyvinylpyrrolidone (PVP), effectively preserved the content of FMDV VLPs during the vacuum freeze-drying process. The immunization trial in mice revealed that the levels of specific antibodies, immunoglobulin G1 (IgG1), interleukin-4 (IL-4), and neutralizing antibodies induced by freeze-dried FMDV VLPs were comparable to those induced by non-freeze-dried FMDV VLPs. The heat treatment results showed that the storage periods of freeze-dried FMDV VLPs at 4, 25, and 37 ℃ were significantly longer than those of non-freeze-dried FMDV VLPs. In conclusion, the selected lyoprotectant formulation effectively improved the stability of FMDV VLPs vaccines. This study provides valuable insights for enhancing the stability of novel subunit vaccines.
Freeze Drying/methods* ; Animals ; Foot-and-Mouth Disease Virus/immunology* ; Mice ; Vaccines, Virus-Like Particle/chemistry* ; Foot-and-Mouth Disease/immunology* ; Vacuum ; Drug Stability ; Mice, Inbred BALB C ; Viral Vaccines/immunology*

ObjectiveTo explore the underlying mechanism of bran-fried Atractylodis Rhizoma （AR） in improving gastrointestinal function by comparing the effects of raw AR and bran-fried AR on the small intestine tissue structure and transport-related protein carriers in rats with spleen deficiency syndrome. MethodSeventy male SD rats were randomly divided into a normal group， a model group， high- and low-dose raw AR groups （10， 2.5 g·kg^-1）， high- and low-dose bran-fried AR groups （10， 2.5 g·kg^-1）， and a compound glutamine group （9 mg·kg^-1）， with 10 rats in each group. Except for the normal group， the other six groups were subjected to the spleen deficiency model induced by the method of bitter and cold breaking stagnated Qi and abnormal hunger and fullness for 21 days. After modeling， each treatment group was given medication orally according to the corresponding doses every day for a total of 14 days， and the normal group and the model group were given an equal volume of normal saline orally. During the treatment period， the general survival status， macroscopic syndrome score， daily increase in body weight and food intake， and rectal temperature of the spleen deficiency rats were evaluated， and after the treatment， the rats were sacrificed. The pathological changes in the small intestine tissues of each group were observed by hematoxylin-eosin （HE） staining. The content of serum 5-hydroxytryptamine （5-HT） was detected by enzyme-linked immunosorbent assay （ELISA）， and the content of serum D-xylose， lactate， and amylase was detected by colorimetry. The levels of free fatty acid receptor 3 （FFA3） and peptide transporter 1 （PepT1） in small intestinal tissues were detected by the Bradford method， and the protein expression of sodium-dependent glucose transporter 1 （SGLT1） and glucose transporter 1 （GLUT1） in small intestinal tissue was detected by immunohistochemistry. Real-time fluorescence-based quantitative PCR was used to detect the mRNA expression of glucose transporter 2 （GLUT2）， sodium/hydrogen exchanger 3 （NHE3）， and 5-hydroxytryptamine receptor 4 （5-HT4R）. ResultCompared with the normal group， the model group exhibited symptoms of spleen deficiency， such as sluggishness， squint， reduced food intake， and lethargy at the end of modelling， damaged basic structure of the small intestinal mucosal epithelium and lamina propria， increased serum lactate and 5-HT content， and decreased serum amylase and D-xylose （P<0.01）. Compared with the model group， all treatment groups showed varying degrees of improvement， with the small intestinal microstructure repaired to different degrees. The daily weight gain， anal temperature， and macroscopic syndrome score of spleen deficiency improved to varying degrees （P<0.05， P<0.01）. The serum lactate and 5-HT content decreased to varying degrees， while the serum amylase and D-xylose content increased to varying degrees （P<0.05， P<0.01）. The PepT1 content in the small intestinal tissues increased， while the FFA3 content decreased to varying degrees. The protein expression of SGLT1 and GLUT1 increased， while the mRNA expression of GLUT2 and NHE3 increased to varying degrees. The mRNA expression of 5-HT4R decreased to varying degrees （P<0.05， P<0.01）. Compared with the high- and low-dose raw AR groups， the high- and low-dose bran-fried AR groups showed significant improvement in general conditions and histopathological improvement of the small intestinal tissues. The daily weight gain， anal temperature， and macroscopic syndrome score of spleen deficiency also improved （P<0.05， P<0.01）. The serum lactate and 5-HT content decreased， while the serum amylase and D-xylose content increased （P<0.05， P<0.01）. The PepT1 content in the small intestinal tissues increased， while the FFA3 content decreased. The protein expression of SGLT1 and GLUT1 increased， while the mRNA expression of GLUT2 and NHE3 increased. The mRNA expression of 5-HT4R decreased significantly （P<0.05， P<0.01）. ConclusionBran-fried AR can improve the spleen deficiency-related symptoms and histopathology of the small intestinal tissues in spleen deficiency model rats. Its mechanism may be related to the regulation of the expression of various transport-related protein carriers and the secretion of various digestive enzymes after stir-frying of AR， thus restoring the absorption and transport function of the small intestine.

OBJECTIVETo study the effect of Jiaweisinisan (JWSNS), a traditional Chinese herbal medicinal recipe, on gastric mucosal ultrastructure and brain-gut axis in rat models of chronic psychological stress and elucidate the mechanism of JWSNS for ameliorating stress-induced gastrointestinal dysfunction.

METHODSSixty rats were randomly assigned into normal control group, model group, 3 JWSNS groups (high, moderate, and small doses), and omeprazole group (n=10). Rat models of chronic psychological stress were established by random stressful stimulations, and following the corresponding interventions, plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) levels were detected using radioimmunoassay, and the mRNA expressions of gastrin receptor in the gastric tissue (GASR) and vasoactive intestinal peptide II receptor (VIPR2) in the jejunal tissue were examined using RT-PCR. Transmission electron microscopy was employed to examine the ultrastructural changes in the gastric mucosa tissue cells of the glandular stomach area and alterations in the intercellular junctions.

RESULTSElectron microscopy revealed obvious damages in gastric mucosal epithelial cell organelles and nuclei in the model rats. These damages were ameliorated after treatments with JWSNS and omeprazole. Compared with the model group, the 3 JWSNS groups and omeprazole group all showed significantly lowered plasma ACTH and CORT levels, increased gastrin receptor mRNA expression and decreased jejunal VIPR2 mRNA expression (P<0.05 or 0.01).

CONCLUSIONJWSNS can obviously ameliorate the pathologies of the gastric mucosa cells, regulate the state of brain-gut axis, and modulate the gastric gastrin receptor and jejunal VIPR2 mRNA expressions in rats with chronic psychological stress.

Adrenal Cortex Hormones ; blood ; Adrenocorticotropic Hormone ; blood ; Animals ; Drugs, Chinese Herbal ; pharmacology ; Gastric Mucosa ; metabolism ; pathology ; ultrastructure ; Hydrocortisone ; blood ; Jejunum ; metabolism ; Male ; Rats ; Rats, Wistar ; Receptors, Bombesin ; metabolism ; Receptors, Vasoactive Intestinal Peptide, Type II ; metabolism ; Stress, Psychological ; pathology