Body surface area-based equivalent dose calculation in tree shrew

Effects of total glucosides of paeony on serum inflammatory cytokines in animal models of rheumatoid arthritis: a systematic review and meta-analysis

Background: Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic synovitis of the affected joints. Total glucosides of paeony (TGP) capsules have been widely used clinically for the treatment of RA with good efficacy and safety. However, its effect on inflammatory cytokines remains unclear. Objectives: This study aimed to summarize the effect of TGP on the expression level of serum inflammatory cytokines in RA animal models and its potential mechanisms. Methods: Six databases were searched up to 14 August 2023, relevant animal experiment studies were screened, data were extracted, and the SYRCLE animal experiment bias risk assessment tool was used for risk assessment. Results: A total of 24 studies were included, including 581 animals. Results showed that compared with the model control group, TGP decreased the levels of TNF-α, IL-1β, IL-6, and PGE2 and increased the levels of TGF-β1 after 1-2 weeks of intervention, decreased the levels of TNF-α, IL-1β, IL-6, IL-2, IL-17, IL-17α, IL-21, VEGF, IFN-γ and PGE2 and increased the levels of IL-10 and IL-4 after 3-4 weeks of intervention, decreased the levels of TNF-α, IL-6, IL-17α and increased the level of IL-10 after 8 weeks of intervention. There was no significant difference in the effects of TGP on the levels of IL-10, IL-17, and IFN-γ after 1-2 weeks of intervention and IL-1 and TGF-β1 after 3-4 weeks of intervention. Conclusion: In summary, based on the existing studies, this study found that compared with the control group of the RA animal model, TGP can reduce the levels of serum pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 and increase the levels of serum anti-inflammatory cytokines such as IL-10, exerting an anti-inflammatory effect by regulating and improving the levels of inflammatory cytokines, and thus alleviating the disease. Given the low quality of the included studies and the lack of sufficient evidence, more high-quality studies are still needed to validate the results of this study.

Genotoxic mode of action and threshold exploration of 2-methyl furan under 120-day sub-chronic exposure in male Sprague-Dawley rats

2-Methylfuran (2-MF) is an important member of the furan family generated during food thermal processing. An in-vivo multiple endpoint genotoxicity assessment system was applied to explore the genotoxic mode of action and threshold of 2-MF. Male Sprague-Dawley rats received 2-MF by oral gavage at doses of 0.16, 0.625, 2.5, and 10 mg/kg.bw/day for 120 days. An additional 15 days were granted for recovery. The Pig-a gene mutation frequency of RET and RBC showed significant increases among the 2-MF groups on day 120. After a 15-day recovery period, the Pig-a gene mutation frequency returned to levels similar to those in the vehicle control. The tail intensity (TI) values of peripheral blood cells at a dose of 10 mg/kg.bw/day significantly increased from day 4 and remained at a high level after the recovery period. No statistical difference was found in the micronucleus frequency of peripheral blood between any 2-MF dose group and the corn oil group at any timepoint. 2-MF may not induce the production of micronuclei, but it could cause DNA breakage. It could not be ruled out that 2-MF may accumulate in vivo and cause gene mutations. Hence, DNA, other than the spindle, may be directly targeted. The mode of action of 2-MF may be that it was metabolized by EPHX1 to more DNA-active metabolites, thus leading to oxidative and direct DNA damage. The point of departure (PoD) of 2-MF-induced genotoxicity was derived as 0.506 mg/kg bw/day.

Tree shrews as a new animal model for systemic sclerosis research

Objective

Systemic sclerosis (SSc) is a chronic systemic disease characterized by immune dysregulation and fibrosis for which there is no effective treatment. Animal models are crucial for advancing SSc research. Tree shrews are genetically, anatomically, and immunologically closer to humans than rodents. Thus, the tree shrew model provides a unique opportunity for translational research in SSc.

Methods

In this study, a SSc tree shrew model was constructed by subcutaneous injection of different doses of bleomycin (BLM) for 21 days. We assessed the degree of inflammation and fibrosis in the skin and internal organs, and antibodies in serum. Furthermore, RNA sequencing and a series of bioinformatics analyses were performed to analyze the transcriptome changes, hub genes and immune infiltration in the skin tissues of BLM induced SSc tree shrew models. Multiple sequence alignment was utilized to analyze the conservation of selected target genes across multiple species.

Results

Subcutaneous injection of BLM successfully induced a SSc model in tree shrew. This model exhibited inflammation and fibrosis in skin and lung, and some developed esophageal fibrosis and secrum autoantibodies including antinuclear antibodies and anti-scleroderma-70 antibody. Using RNA sequencing, we compiled skin transcriptome profiles in SSc tree shrew models. 90 differentially expressed genes (DEGs) were identified, which were mainly enriched in the PPAR signaling pathway, tyrosine metabolic pathway, p53 signaling pathway, ECM receptor interaction and glutathione metabolism, all of which are closely associated with SSc. Immune infiltration analysis identified 20 different types of immune cells infiltrating the skin of the BLM-induced SSc tree shrew models and correlations between those immune cells. By constructing a protein-protein interaction (PPI) network, we identified 10 hub genes that were significantly highly expressed in the skin of the SSc models compared to controls. Furthermore, these genes were confirmed to be highly conserved in tree shrews, humans and mice.

Conclusion

This study for the first time comfirmed that tree shrew model of SSc can be used as a novel and promising experimental animal model to study the pathogenesis and translational research in SSc.

Oral Intake of Inosine 5'-Monophosphate in Mice Promotes the Absorption of Exogenous Fatty Acids and Their Conversion into Triglycerides though Enhancing the Phosphorylation of Adenosine 5'-Monophosphate-Activated Protein Kinase in the Liver, Leading to Lipohyperplasia

Inosine 5'-monophoaphate (IMP) is a food additive that promotes serious lipohyperplasia in the liver of C57/KsJ-db/db (db/db) mice. Thus, IMP taken orally by healthy mice might also damage their health. To date, how IMP affects health after being taken by healthy animals is still unclear. Therefore, we investigated the health of C57BL/6J mice affected by IMP intake. Our data revealed that C57BL/6J mice administered 255 μM IMP daily via oral gavage for 4 months caused hyperlipidemia and an increase in body fat rate. The expressions of acetyl-CoA carboxylase 1 (ACC1) and phosphorylated acetyl-CoA carboxylase 2 (ACC2) in hepatocytes increased though the administration of IMP, promoting the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). The conversion of acetyl-CoA into triglycerides (TGs) was promoted by ACC1. These TGs were transported from the hepatocytes to avoid the development of non-alcoholic fatty liver disease (NAFLD), causing a deficiency of acetyl-CoA in the liver, and then, the increased phosphorylated ACC2 promoted the cytoplasm fatty acids entering the mitochondria and conversion into acetyl-CoA through the fatty acid β-oxidation pathway, causing a deficiency in fatty acids. Therefore, the liver showed enhanced absorption of exogenous fatty acids, which were converted into TGs, causing lipohyperplasia. In conclusion, an excessive IMP intake promotes metabolic dysfunction in adipose tissue.

The regulation of expression and splicing of transcription factors are related to the muscle damage caused by radiation in tree shrews

Radiotherapy-induced muscle injury (RIMI) is a major complication of radiotherapy for nasopharyngeal carcinoma. Transcription factor (TF) expression and alternative splicing are crucial events in transcriptional and posttranscriptional regulation, respectively, and are known to be involved in key signaling pathways contributing to a variety of human disorders, including radiation injury. To investigate the TFs and alternative splicing events involved in RIMI, we constructed a tree shrew model as described previously in which the RIMI group received 20 Gy of irradiation on the tensor veli palatini (TVP) muscles. The irradiated muscles were evaluated by RNA sequencing (RNA-seq) 6 months later, and the results compared with those for normal TVP muscles. The alt5p and alt3p events were the two main types of differentially regulated alternative splicing events (RASEs) identified via the Splice sites Usage Variation Analysis (SUVA) software, and these RASEs were highly conserved in RIMI. According to functional enrichment analysis, the differentially RASEs were primarily enriched in pathways related to transcriptional regulation. Furthermore, we identified 16 alternative splicing TFs (ASTFs) in ASTF-differentially expressed gene (DEG) networks based on co-expression analysis, and the regulatory networks were chiefly enriched in pathways linked to cell proliferation and differentiation. This study revealed that RASEs and ASTF-DEG networks may both play important regulatory roles in gene expression network alteration in RIMI. Future studies on the targeting mechanisms and early interventions directed at RASEs and ASTF-DEG networks may aid in the treatment of RIMI.

Biopharmaceutical, preclinical pharmacokinetic and pharmaco-dynamic investigations of an orally administered novel 3-nbutylphthalide prodrug for ischemic stroke treatment

Ischemic stroke (IS) has been contributing in leading causes of disability and death worldwide and the cases are still increasing. In China, naturally sourced compound 3-n-butylphthalide (NBP) is widely applied in clinical practice for IS treatment with established evidences of efficacy and safety. However, NBP is an oily liquid at room temperature and has no active brain targeting ability, quite limiting its broader application in clinical practice. Via intravenous injection (i.v.) a prodrug compound (DB1) we previously developed deriving from NBP had dramatically enhanced the pharmacological effects, where however, this i.v. route still discount future patient compliance. As druggability of DB1 in oral administration has yet to be elaborated, the current study intended to systemically investigate its biopharmaceutical properties, so as to further consider clinical applicability of DB1 oral preparations. Additionally, pharmacokinetics and pharmacodynamics of DB1 via oral administered route were also studied, illustrating broad potential of further DB1 medicine development. After the derivation, aqueous solubility of DB1 improved 3∼400 folds compared with NBP in various pH media, and n-octanol/water partition coefficient kept in the range of 0∼2. In situ single-pass intestinal perfusion on rats showed effective permeability coefficient of DB1 over 10^-2 cm/s. In contrast to NBP, oral administration of DB1 could display significant enhanced bioavailability in rats and achieve increased accumulation in brain tissues. As expected, DB1 effectively alleviated oxidative stress damage and reduced infarct volume on ischemia/reperfusion (I/R) modeled rats, resulting in reduced mortality. Additionally, this new prodrug did not add any safety concerns based on NBP. Therefore, biopharmaceutical results and preclinical pharmacodynamic evidences support the conclusion that an oral administration of DB1 may have a good potential for clinical IS treatment.

An Investigation of the Mechanisms of Radiation-Induced Muscle Injury in a Tree Shrew (Tupaia belangeri) Model

Background

Animal models suitable for investigating mechanisms behind radiation-induced muscle injury are lacking. We developed a tree shrew model of such injury and investigated pathological changes and mechanisms.

Methods

Animals were divided into control (n = 5), radiation-induced acute injury (n = 5), and radiation-induced chronic injury (n = 5) groups. Tensor veli palatini (TVP) muscles of acute injury and chronic injury groups were dissected under a microscope at 1 and 24 weeks after radiation therapy, respectively. TVP muscles were stained with HE and Masson to visualize pathological changes. ELISA was performed to measure oxidative injury. RT-qPCR and immunohistochemical staining was performed to measure expression levels of miR-206 and histone deacetylase 4 (HDAC4).

Results

Compared to the control group, acute injury group showed a significant decrease in miR-206 expression (.061 ± .38, P < .05) and a significant increase in HDAC4 expression (37.05 ± 20.68, P < .05). Chronic injury group showed a significant decrease in miR-206 expression (.23 ± .19, P < .05) and a significant increase in HDAC4 expression (9.66 ± 6.12, P < .05).

Discussion

A tree shrew model of radiation-induced muscle injury was established by exposing TVP muscle region to radiation of 20-Gy. Experimental results indicated that injury caused by radiation persisted despite gradual healing of the TVP muscle and miR-206 regulatory pathway plays a key role in regulating radiation-induced muscle injury.