Abstract:

To investigate the effect of carboxymethyl pachymaran (CMP) on life extension of colon tumor 26
(CT26)-bearing mice and mitigating the side effects caused by chemotherapy with cyclophosphamide (CTX). Methods: CT26
tumor-bearing mouse models were established by subcutaneous transplantation into mice, and they were randomly divided
into model, CTX and CTX + CMP groups for toxicity test. The model, and low-, medium- and high-dose CMP, groups
were used for life extension test. Peripheral white blood cells (WBC), bone marrow nucleated cells (BMNC), percentage
tumor inhibition, and visceral organ indexes were tested by biochemical assays. The expression of signal regulating protein
alpha (SIRP-α) and macrophage surface marker (F4/80) in tumor tissues were detected through immunohistochemistry.
Meanwhile, life extension rate and median survival period were observed. Results: CMP could increase the lower spleen
index and thymus index, and the decreased levels of WBC and BMNC induced by CTX, antagonize the increase in liver
index, and reduce the expression of SIRP-α and F4/80 in tumor tissues. In addition, CMP also could extend the survival time
of CT26 tumor-bearing mice. Conclusion: CMP can obviously reduce the side effects of CTX, regulate the expression of
tumor immune-related proteins, and prolong the survival time of CT26 tumor -bearing mice.

Key words: carboxymethyl pachymaran (CMP), colon cancer, immune regulation, cyclophosphamide (CTX), reducing toxicity, life extending