ZIF-8 as efficient carriers for polysaccharide from Tetrastigma Hemsleyanum Diels et Gilg in acute lung injury induced by lipopolysaccharides.

Acute lung injury (ALI) is a critical respiratory syndrome significantly impacting patient health. Tetrastigma hemsleyanum Diels et Gilg (Sanyeqing, SYQ) is a traditional Chinese medicine and its polysaccharides (SYQP) have demonstrated efficacy in counteracting lipopolysaccharide-induced ALI. This study characterized the structure of SYQP and synthesized the SYQP@ZIF-8 composite using biomimetic mineralization, evaluating encapsulation and release efficiency. The biocompatibility of SYQP@ZIF-8 in vitro was assessed by the CCK-8 colorimetric assay and hemolytic activity. Inflammatory cytokine was measured to evaluate the therapeutic effect. The efficacy of SYQP@ZIF-8 in lung injury was assessed using a mice ALI model. Characterization showed SYQP as a homogeneous α-type polysaccharide, comprising galactose, mannose, glucuronide, glucose, galacturonide, and arabinose, with a molecular weight of 516.94 kDa. SYQP@ZIF-8 exhibited high encapsulation rate (> 90 %), rapid pH-responsive release (within 60 min up to ~100 %), low toxicity and favorable hemolytic characteristics. Furthermore, it demonstrated reduced inflammatory cytokine secretion compared to SYQP, along with a superior inhibitory effect. The outcomes of in vivo experiments, including a decrease in the W/D ratio and LDH activity, further confirmed the efficacy of SYQP@ZIF-8 in treating LPS-induced ALI. In conclusion, SYQP@ZIF-8 released SYQP in acidic inflammatory conditions, outperforming SYQP alone in treating ALI.