Lycium barbarum polysaccharide inhibits the growth of rat glioma by regulating the blood-brain barrier / 肿瘤

ABSTRACT

Objective: To investigate the inhibitory effect of lycium barbarum polysaccharides (LBPs) on growth of glioma in rats and its possible mechanism. Methods: The rats were divided into LBP A group, LBP B group, LBP C group, LBP D group, LBP E group and F group (control group) to be fed with 400, 200, 100, 50 and 25 mg · kg-1 · d-1 LBP and drinking water, respectively. The model of rat C6 glioma in situ was established through surgery. The survival of the glioma-bearing rats was observed, and the tumor volume was examined. The percentage of CD3+CD8+T cells in rat blood was detected by FCM method. The expressions of CD3 and CD8 in glioma tissues in rats were detected by immunohistochemistry. After injection of Evans blue solution through femoral vein, the effect of LBP on the permeability of blood-brain barrier in rats was observed, and the change of ultrastructure of brain tissues was observed under a scanning electron microscope. The expressions of CD8 and annexin A1 (ANXA1) mRNAs and ANXA1 protein in glioma tissues in rats were detected by real-time fluorescent quantitative-PCR and Western blotting, respectively. Results: The survival of glioma-bearing rats in LBP A, LBP B and LBP C groups was superior to that in F group (all P < 0.05). The tumor volume of glioma-bearing rats in LBP A, LBP B and LBP C groups was smaller than that in F group (all P < 0.05). The percentage of CD3+CD8+T cells in blood of glioma-bearing rats in LBP C group was higher than that in F group [(18.9± 1.4)% vs (11.5±0.7)%, P < 0.01]. The number of CD3+ and CD8+ T cells in glioma tissues in rats in LBP C group was higher than that in F group (both P < 0.01). The amount of Evans blue solution into the brain tissues in LBP C group was increased, the capillary endothelial cells were shrinkable, and the basement membrane was uneven with partial fracture. The expression level of CD8 mRNA in glioma tissues in rats was up-regulated (P < 0.01), whereas the expression levels of ANXA1 mRNA and protein were down-regulated (both P < 0.01). Conclusion: LBPs can inhibit the growth of glioma and prolong the survival of glioma-bearing rats. The mechanism may be related to the inhibitory effect of LBPs on the growth of tumor by regulating the blood-brain barrier and promote the invasion of CD8+T cells into the brain.