The Protein Therapy of Kallikrein in Cerebral Ischemic Reperfusion Injury

Objective: Biomacromolecule like exogenous Kallikrein is difficult to pass through biomembrane and blood brain barrier. So, the use of exogenous Kallikrein for the therapy of nervous system diseases is restricted. We constructed the Protein Transduction Domain-Kallikrein (PTD-Kallikrein), checked its function of penetration and biotoxicity, and observed its influence on neurons and ischemic brain tissues. Methods: PTD-Kallikrein (tissue kallikrein) was prepared by chemical synthesis. After PTD-Kallikrein injected 2.5 hours, rats brains were taken out and contents of Kallikrein were quantitated to observe the function of passing through blood brain barrier. Cell survival rate were measured by XTT methods to determine the peptide's biotoxicity. Apoptosis were inspected by TUNEL. PTD-Kallikrein was administrated immediately after cerebral ischemia. 24h later, infarct volume was determined by TTC stain and IL-1 beta, TNF-alpha as well as PGE(2) were measured by ELISA. Results: 1. PTD-Kallikrein can pass through the biomembrane and blood brain barrier; 2. PTD-Kallikrein itself has no obviously biotoxicity. 3. PTD-Kallikrein increases cell survival rate, decreases neurons apoptosis during OGD/recovery; 4. HOE140 inhibits the effects of PTD-Kallikrein. 5. PTD-Kallikrein improves neurological impairment, decreases the infarct volume, and inhibits the release of IL-1 beta, TNF-alpha, PGE(2). 6. HOE140 inhibits the effects of PTD-Kallikrein on ischemia-reperfusion injury. Conclusions: 1. PTD-Kallikrein can pass through the biomembrane and BBB efficiently and itself has no obviously biotoxicity. 2. PTD-Kallikrein has neuroprotective effect on neurons and cerebral ischemia injury. 3. PTD-Kallikrein is partially mediated by B2 receptors.