Professor Liu Zhiyu, Fujian Fisheries Research Institute, et al.: Immunomodulatory mechanism of erythroxyphyllin to cyclophosphamide-induced immunosuppressive mice

Malignant tumor has become a serious threat to human health and life safety of common diseases, chemotherapy is still one of the main treatments, however, chemotherapy drugs in the destruction of tumor cells at the same time, will lead to intestinal inflammation of patients caused by intestinal flora disorder, destruction of intestinal epithelial barrier and intestinal immunity, thereby causing other diseases, such as bone marrow suppression, liver damage and other diseases; In addition, clinical diagnosis shows that patients receiving long-term chemotherapy will have immunosuppressive conditions, resulting in the body's ability to respond to antigens is suppressed or even lost, so most patients will be given appropriate immunomodulators during treatment to alleviate immunosuppression
.

In the early stage, the research group extracted a red phygal polysaccharide (BFP) with a molecular weight of about 333 kDa from red hair algae, which is mainly composed of
five monosaccharides: rhamnose, arabinose, mannose, glucose and galactose 。 Wu Jingna from the Engineering Research Center of Marine Biomedical Resources of Fujian Province and Liu Zhiyu* from Fujian Fisheries Research Institute of Xiamen Medical College and Fujian Key Laboratory of Marine Bioculture and High-value Utilization constructed an immunosuppressive mouse model by intraperitoneal injection of CTX, and preliminarily explored the protective effect and mechanism of BFP in immunosuppressed mice from multiple perspectives, in order to provide a theoretical basis
for the development of BFP into a foodborne immunomodulator.

1.
Effect of BFP on non-specific immunity in immunosuppressed mice

It can be seen from Figure 1A that compared with the blank control group, the activity of NK cells in the model group was significantly reduced (P<0.
01); compared with the model group, the activity of NK cells was significantly enhanced in the low, medium and high-dose BFP treatment group (P<0.
01); the enhancement effect of high-dose BFP was comparable to that of the positive control group, and the activity of NK cells was as high as 57.
36%.
<b10> 。 It can be seen from Figure 1B that compared with the blank control group, the phagocytic ability of neutral red in mouse macrophages in the model group is significantly reduced (P<0.
01); compared with the model group, the ability of macrophages to phagocytose neutral red can be slightly improved in the low-dose BFP treatment group, but there is no significant significance (P>0.
05), and the promotion effect of the medium and high-dose groups on the ability of macrophages to phagocytose neutral red reaches a very significant level (P<0.
01<b11>).
。 It can be seen from Fig.
1C and D that compared with the blank control group, the carbon clearance index K and phagocy index α of mice in the model group are significantly reduced (P<0.
01), compared with the model group, the carbon clearance index K (P<0.
01) can be significantly increased in the medium and high BFP treatment groups, and the phagocytosis index α (P<0.
05, P<0.
01)<b12> can be significantly increased in the low, medium and high BFP treatment groups.

2.
Effects of BFP on humoral immunity and cellular immunity in immunosuppressed mice

Table 2 shows that compared with the blank control group, the proliferation rate, CD4+ T cell ratio, ^CD4+/CD8⁺ of mice in the model group were compared All are significantly reduced; Compared with the model group, the low-dose BFP treatment group could promote the proliferation of mouse T lymphocytes, but the effect was not significant (P>0.
05), the proliferation effect of the medium-dose BFP treatment group reached a significant level (P<0.
05), and the high-dose BFP treatment group reached a very significant level (P<0.
01), the cell proliferation rate was as high as 18.
58%, and the proliferation effect was comparable to that of the positive control group.
Compared with the model group, low- and medium-dose BFP intervention can significantly increase the proportion of CD4+ T cells in blood (P<0.
05), and the high-dose BFP treatment group can significantly increase the proportion of CD4+ T cells in blood (P<0.
01), and compared with the model group<b15>, low- and medium-dose BFP treatment can reduce the proportion of CD8⁺ T cells.
However, the effect was not significant (P>0.
05), while high-dose BFP intervention significantly reduced the proportion of CD8+ T cells (P<0.
05)<b17> and significantly increased CD4+/CD8⁺
.
Compared with the blank control group, the proportion of mouse helper T cells (Th) 17 (CD4+IL-17⁺ T cells) in the model group was significantly increased, and the proportion of regulatory T cells (Treg) (CD4⁺CD25⁺ T cells) did not change significantly.
Compared with the model group, low, medium and high BFP treatment could significantly or very significantly reduce the proportion of Th17 (CD4+IL-17⁺ T cells) (P<0.
05, P<0.
01), but had no significant effect on the proportion of Treg (CD4<b114>+CD25⁺ T cells) (P>0.
05).
High-dose BFP intervention significantly reduced the proportion of ^CD3-CD19+ B cells (P<0.
01)<b120> in the blood of immunosuppressed mice.

It can be seen from Figure 2 that compared with the blank control group, the serum hemolysin level of mice in the model group is significantly reduced.
Compared with the model group, the effect of low and medium BFP treatment groups on serum hemolysin levels was not significant (P>0.
05), while the promotion effect of high dose BFP reached a very significant level (P<0.
01), and was slightly higher than that of the positive control group<b10>.

It can be seen from Figure 3 that compared with the blank control group, the mass concentrations of immune-related cytokines (IL-2, IL-6, TNF-α, INF-γ), IgA and IgG in the serum of mice in the model group decreased significantly (P<0.
01), and compared with the model group, the low, medium and high BFP dose treatment groups could significantly promote the release of IL-2, IL-6, TNF-α and INF-γ (P<0.
01) and significantly increase the production of IgA and IgG (P<0.
01) <b10>。

3.
Effect of BFP on the expression level of immune-related cell surface receptors and cytokines in the intestinal tissues of immunosuppressed mice

As shown in Table 3, compared with the blank control group, the relative expression levels of TLR2 and TLR4 mRNA in the colon tissues of mice in the model group increased significantly (P<0.
05) after CTX treatment, while other TLR and NLR changes were not significant (P>0.
05), and the transcription levels of immunocorrelated factors (IL-6, TNF-α) were significantly higher than those in the blank control group (P<0.
05).
<b10> 。 Compared with the model group, the transcription levels of TLR2 and TLR4 (P<0.
05) were significantly reduced in the intervention of the medium and high dose BFP groups, while the TNF-α gene expression levels in the medium and high dose groups were significantly lower than those in the model group (P<0.
05), and the expression levels of IL-6 genes at low, medium and high doses were significantly reduced compared with those in the model group (P<0.
05), but IL-6 and TNF-α were The trend of mRNA relative expression level is different<b11> from that of IL-6 and TNF-α mass concentrations in serum.

The results are shown in
Figure 4.
Compared with the blank control group, the relative expression levels of TLR2, TLR4, IL-6 and TNF-α proteins in the colon tissues of mice in the model group were significantly increased (P<0.
01) after CTX treatment, and the relative expression levels of TLR2 and TLR4 proteins were significantly lower than those in the model group (P<0.
01) after low, medium and high dose BFP intervention, and the relative expression levels of IL-6 and TNF-α proteins were significantly reduced, which was consistent with the gene expression detection results<b11> 。

Conclusion

BFP has a good regulatory effect on non-specific, humoral and cellular immunity of CTX-induced immunosuppressed mice, and can effectively improve the immune function suppression
caused by CTX 。 At the same time, BFP can downregulate the expression level of intestinal related immune cell surface receptor (TLR2, TLR4) genes and proteins in immunosuppressed mice, and reduce the expression level of immune-related factor (IL-6, TNF-α) genes and proteins.

About the corresponding author

Liu Zhiyu, Ph.
D.
, professor-level senior engineer, doctoral supervisor, has long been engaged in aquatic product processing technology and quality and safety research
.
He is currently the deputy director of Fujian Fisheries Research Institute, the director of the National Marine Fish Processing Technology Research and Development Sub-center (Xiamen), the director of the Fishery Product Quality Supervision and Testing Center (Xiamen) of the Ministry of Agriculture and Rural Affairs, and the director of
the Fujian Marine and Fishery Judicial Appraisal Center.
In recent years, he has presided over the research of 20 national, provincial and ministerial scientific research projects, including the national marine public welfare industry scientific research project, the sub-project of the national key research
and development plan, the national marine regional innovation and development demonstration project, and the major science and technology project of Fujian Province.
It has undertaken the formulation
of 6 national standards and industry standards.
The scientific research achievements have won the first prize of Fujian Provincial Science and Technology Progress Award, the first prize of National Marine Science and Technology Award once, the second prize of National Marine Science and Technology Innovation Award once, and the third prize of Provincial Science and Technology Progress Award 6 times; 15 authorized invention patents; He has published more than 100 academic papers as the first author or corresponding author, and more than 20 papers included in SCI and EI, and was selected as the tenth batch of top talents
in Xiamen.

First author bio

Jingna Wu, Ph.
D.
, is a lecturer in the Department of Pharmacy, Xiamen Medical College, mainly engaged in the development and utilization of new marine foods, marine functional foods and marine drugs
.
He has presided over 11 scientific research projects such as State Oceanic Administration, Fujian Provincial Department of Science and Technology, Fujian Provincial Department of Education, Fujian Provincial Oceanic and Fisheries Bureau and Xiamen Science and Technology Bureau; Presided over and participated in the formulation of
5 national industry standards and local standards in Fujian Province.
The scientific research achievements have won the first prize of marine science and technology of the State Oceanic Administration once, the first prize of Fujian Science and Technology Progress Award, the third prize of Fujian Science and Technology Progress Award twice, and the Fujian Province Marine and Fishery Achievement Contribution Award once.
6 authorized national invention patents; He has published more than 30 academic papers as the first author
.

This article "Immunomodulatory Mechanism of Red Hairy Algal Polysaccharide on Cyclophosphamide-Induced Immunosuppressive Mice in Mouse" is from Food Science, Vol.
43, No.
19, 2022, pp.
174-183, authors: Wu Jingna, Pan Nan, Chen Xiaoting, Chen Bei, Liu Zhiyu
.
DOI:10.
7506/spkx1002-6630-20210929-351
。 Click to view information about the article