熟地黄对辐射损伤后小鼠 T 细胞与 NK 细胞介导免疫重建的恢复作用

Functional impairment of T and NK cells following irradiation (IR) undermine anti-tumor immune responses.

This study aimed to investigate the characteristics of T-cell and NK-cell reconstitution in mice following low-dose radiation-induced injury and the restorative effects of Rehmanniae Radix Praeparata (RRP).

At various time points post-IR, splenic/thymic indices, complete blood count and CD3+ T, CD4+ T, CD8+ T and NK cells, as well as CD80, CD86, MHC-I and MHC-II were assessed. Type 1 T helper (Th1), Type 1 cytotoxic (Tc1), Type 1 NK (NK1), regulatory T (Treg) and Th17 cells along with IL-12, IL-15, T-bet and foxP3 were also evaluated with or without RRP treatment.

Additionally, a B16 melanoma lung metastasis model in irradiated mice was used to confirm the restorative effects of RRP. CD3+, CD4+, CD8+ T and NK cells decreased significantly on Days 4 to 6 and largely recovered by Days 9 to 11 post-IR. The expression of CD80, CD86 and MHC-II reduced on Day 6 and recovered by Day 11.

However, interferon (IFN)- production by Th1, Tc1 and NK1 cells remained lower, whereas Tregs were elevated. RRP effectively enhanced IFN- production from Th1, Tc1 and NK1 cells and suppressed Tregs by increasing T-bet and decreasing foxP3 expression, thereby significantly reduced the tumor burden.

These findings suggest that T-Cell and NK-Cell-mediated inefficient reconstitution following IR was characterized by an decrease of Th1, Tc1 and NK1 cells and an increase of Tregs, RRP effectively promoted the functional reconstitution of T-cell and NK-cell subsets, thereby enhancing anti-tumor immunity after IR.