Background: Porcine parvovirus (PPV) is a single-stranded DNA virus that causes porcine reproductive failure. It is of critical importance to study PPV pathogenesis for the prevention and control of the disease. NS1, a PPV non-structural protein, is participated in viral DNA replication, transcriptional regulation, and cytotoxicity. Our previous research showed that PPV can activate nuclear factor kappa B (NF-κB) signaling pathway and then up-regulate the expression of interleukin (IL)-6. Objectives: Herein, the purpose of this study is to determine whether the non-structural protein NS1 of PPV also has the same function. Methods: Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay, western blot, immunofluorescence assay and small interfering RNA (siRNA) were used. Results: Our findings demonstrated that PPV NS1 protein can up-regulate the expression levels of IL-6 and tumor necrosis factor-alpha in a dose-dependent manner. Moreover, PPV NS1 protein was found to induce the phosphorylation of IκBα, then leading to the phosphorylation and nuclear translocation of NF-κB. In addition, the NS1 protein activated the upstream pathways of NF-κB. Meanwhile, TLR2-siRNA assay showed TLR2 plays an important role in the activation of NF-κB signaling pathway induced by PPV-NS1. Conclusions These findings indicated that PPV NS1 protein induced the up-regulated of IL-6 expression through activating the TLR2 and NF-κB signaling pathways. In conclusion, these findings provide a new avenue to study the innate immune mechanism of PPV infection.

Coronavirus infection can cause serious respiratory and digestive system diseases in hu-mans and animals.In recent years,the frequent outbreaks and newly outbreaks of coronavirus in-fection have threatened global public health and the development of livestock and poultry.Howev-er,the development of anti-coronavirus drugs and vaccines was restricted due to the insufficient understanding of the mechanisms of coronavirus pathogenesis and cross species transmission.Re-verse genetic manipulation technology is a powerful tool in virological research,which can be used for the study of pathogenesis mechanisms,replication mechanisms and function analysis of protein.It is also be used in the development of attenuated or gene labeled vaccines,and antiviral drugs.Due to the large genome and complex structure of the coronavirus,the reverse genetic manipulation technology of coronavirus has been lagging for a long time.With the continuous updating of molec-ular biology methods,various new construction strategies have emerged.This article focuses on the construction strategy of the reverse genetic operating system for coronavirus,as well as its applica-tion in virus transmission and pathogenic mechanisms,and development of vaccines,which will provide favorable tools for the prevention and control of the coronavirus infection.

OBJECTIVE To investigate the improvement effects and mechanism of Xiangsha yiwei tang on gastric mucosal injury in rats with chronic atrophic gastritis （CAG）. METHODS Rats were randomly assigned into normal control group， model group， Xiangsha yiwei tang low-， medium- and high-dose groups （6， 12， 18 g/kg， calculated by crude drug）， and high-dose group of Xiangsha yiwei tang+740 Y-P [Xiangsha yiwei tang 18 g/kg+transforming growth factor β1/phosphatidyl inositol 3 kinase/ protein kinase B（TGF-β1/PI3K/Akt） pathway activator group 740 Y-P 10 mg/kg]， with 18 rats in each group. Rats in each group were administered the corresponding drugs via oral gavage or injection， once daily， for 4 consecutive weeks. Gastric mucosal blood flow， the levels of serum gastrointestinal hormones [including motilin （MTL）， gastrin （GAS）， and pepsinogen （PP）]， as well as inflammatory cytokines [including tumor necrosis factor- α （TNF- α）， interleukin-1β （IL-1β）， IL-6] in rats were measured. Pathological damage to gastric mucosal tissue was observed in rats； the apoptotic rate of gastric mucosal cells was detected. The expressions of TGF-β1/PI3K/Akt signaling pathway-related proteins and apoptosis-related proteins [including B-cell lymphoma-2 （Bcl-2） and Bcl-2-associated X protein （Bax）] in the gastric mucosal tissues of rats were assessed. RESULTS Compared with normal control group， model group had abnormal gastric mucosal tissue structure， with shedding of gastric mucosal epithelial cells， and prominent infiltration of inflammatory cells. Gastric mucosal blood flow， the serum levels of MTL， GAS， PP， and Bcl-2 protein expression were lowered significantly， while serum levels of TNF-α， IL-1β and IL-6， apoptosis rate， protein expressions of Bax and TGF-β1， the phosphorylations of PI3K and Akt were increased significantly （P＜0.05）. Compared with model group， Xiangsha yiwei decoction groups exhibited attenuated histopathological injuries in gastric mucosal tissues， reduced inflammatory cell infiltration， and significant improvements in the aforementioned quantitative parameters （P＜0.05）. Compared with high-dose group of Xiangsha yiwei tang， high-dose group of Xiangsha yiwei decoction combined with 740 Y-P exhibited significantly aggravated histopathological injuries in gastric mucosal tissues， and the aforementioned quantitative parameters were markedly reversed （P＜0.05）. CONCLUSIONS Xiangsha yiwei tang can alleviate gastric mucosal damage in CAG rats， and its mechanism of action is related to the inhibition of TGF-β1/PI3K/Akt signaling pathway.