Protective effect of a polysaccharide from stem of Codonopsis pilosula against renal ischemia/reperfusion injury in rats

In this study, we purified a homogeneous polysaccharide (S-CPPA1) with a molecular weight (Mw) of 133.2 kDa from the stem of Codonopsis pilosula for the first time. Gas chromatography (GC) analysis identified that S-CPPA1 contained glucose, galactose, and arabinose with a molar ratio of 10.5:3.4:1.7, along with a trace of mannose. Methylation analysis suggested S-CPPA1 was a branched polysaccharide, with five glucosidic linkage forms, namely (1→4)-linked Glcp (residue A), (1→6)-linked Galp (residue B), (1→2,6)-linked Glcp (residue C), (1→5)-linked Araf (residue D), and non-reducing terminal (1→)-linked Glcp (residue E). The protective effect of S-CPPA1 on kidney ischemia/reperfusion (I/R) injury was also evaluated. Blood urea nitrogen (BUN), creatinine and TNF-α levels, as well as lactate dehydrogenase (LDH) and alanine transaminase (AST) activities were elevated in the I/R group as compared to the sham group. On the other hand, S-CPPA1 treatment reversed all these biochemical indices, as well as histopathological alterations, which were induced by I/R. The findings imply that S-CPPA1 plays a causal role in the protection against I/R-induced renal injury and its renoprotective effect is probably mediated by inhibiting the proinflammatory cytokine TNF-α release.