The enhancing effect of tomato lectin modified liposomes of insulin on oral absorption in mice
Zhang, N.; Ping, Q-neng.; Xu, W-fang.
Yao Xue Xue Bao 39(5): 380-384
2004
ISSN/ISBN: 0513-4870 PMID: 15338884 Document Number: 584233
Aim: This study was conducted to investigate the enhancing effect of tomato lectin (TL) modified liposomes on insulin absorption through the gastrointestinal (GI) tract in mice. Methods: TL-phosphatidylethanolamine (PE) conjugate (TL-PE) was synthesized by using carbodiimide cross-linking method, then the compound was incorporated into the conventional liposomes of insulin. An agglutination test was performed to examine TL biological activities after synthesis and incorporation. TL modified liposomes were administered orally to normal or diabetic mice at an insulin dose of 350 U kg-1. The hypoglycaemic effect was determined according to blood glucose level. Results: Blood glucose levels of normal mice were reduced by modified liposomes: 85+or-5% at 4 hours, 54+or-11% at 8 hours and 57+or-6% at 12 hours after oral administration. However, the conventional liposomes and saline showed no hypoglycaemic effect. Blood glucose levels of diabetic mice were obviously reduced by TL modified liposomes: 38+or-13% at 4 hours, 50+or-15% at 8 hours and 50+or-16% at 12 hours. Conclusion: TL modified liposomes promote the oral absorption of insulin due to specific-site combination on GI cell membrane.