Polysaccharides of Aloe vera induce MMP-3 and TIMP-2 gene expression during the skin wound repair of rat.

Polysaccharides are the main macromolecules of Aloe vera gel but no data about their effect on extracellular matrix (ECM) elements are available. Here， mannose rich Aloe vera polysaccharides (AVP) with molecular weight between 50 and 250 kDa were isolated and characterized. Open cutaneous wounds on the back of 45 rats (control and treated) were daily treated with 25mg (n=15) and 50 mg (n=15) AVP for 30 days. The levels of MMP-3 and TIMP-2 gene expression were analyzed using real time PCR. The levels of n-acetyl glucosamine (NAGA)， n-acetyl galactosamine (NAGLA) and collagen contents were also measured using standard biochemical methods. Faster wound closure was observed at day 15 post wounding in AVP treated animals in comparison with untreated group. At day 10 post wounding， AVP inhibited MMP-3 gene expression， while afterwards MMP-3 gene expression was upregulated. AVP enhanced TIMP-2 gene expression， collagen， NAGLA and NAGA synthesis in relation to untreated wounds. Our results suggest that AVP has positive effects on the regulation of ECM factor synthesis， which open up new perspectives for the wound repair activity of Aloe vera polysaccharide at molecular level.