Changes of pdgfr-β+ microvascular wall cells in blood-brain barrier permeability of SD rats after status epilepticus

Abstract

Objective To investigate the blood-brain barrier permeability of platelet-derived growth factor receptor-β+ (pdgfr-β+ ) vascular wall cells at 2h, 24h, 3 d, 7 d, 14 d and 21 d after lithium-pilocarpine-induced status epilepticus. Methods One hundred and thirty-five clean male Sprague-Dawley rats were randomly divided into control group(n=15)and model group(n=120). The model group was divided into 2h, 24h, 3d, 7d, 14d and 21d after SE.We evaluated the permeability of blood-brain barrier in hippocampus of rats in each group after status epilepticus by Evans blue method and wet and dry weight method.We observed the ultrastructural changes of pericytes and blood-brain barriers at different stages after onset by electron microscopy.We used Western Blot to detect the expression of pericyte marker pdgfr-β and α-SMA in hippocampus at different stages after onset. Results (1) The blood-brain barrier permeability increased after epileptic seizures(P<0.05), and the permeability was the highest at 24h after onset(P<0.01), and gradually returned to normal after 3d and later.(2) Transmission electron microscopy showed that the ultrastructure of cerebral microvascular pericytes and their basement membranes were degenerated after SE.(3) Western blot showed that the expression level of pdgfr-β and α-SMA at 24 h after SE was significantly higher than that of the control group(P<0.05), and gradually became stable after 3d and later. Conclusion Pdgfr-β+ microvascular wall cells in brain microvessels may be involved in the opening of blood-brain barrier after status epilepticus, and may be dedicated to the conversion of disease into refractory epilepsy. Key words: Status epilepticus; Pericyte; Blood-brain barrier; SD Rat; platelet-derived growth factor receptor-β