RESUMEN
Objective To explore the feasibility of fabricating a self-powered and implantable stimulator . Methods Based on pyroelectric effect and high penetrability of infrared ray , an implantable stimulator was designed and fabricated .The electrical performance of stimulator was measured under infrared ray illumination .We conducted the animal experiments in vitro and in vivo to observe the response of gastrocnemius contraction under stimulation .Results The stimulator could output the electrical signal under the periodical infrared ray illumination .The output voltage and current were proportional to the intensity of infrared ray ,which could reach up to 1 .2 V . A real-time electrical stimulation of frog gastrocnemius was conducted and obvious contraction was observed .The tension values increased with the increase of infrared intensity .We further carried out the in vivo experiment with a frog in order to evaluate the performance of the stimulator after being implanted into the body . The gastrocnemius would also be made to contract even though the infrared intensity decayed when through the skin .Conclusion The proposed pyroelectric stimulator can be self-powered and controlled through near-infrared illumination .This study can provide some guidance for solving the problems of implantable power .
RESUMEN
Objective To explore the role of heme oxygenase-1 (HO-1) in the central nervous system after brain trauma. Methods Forty-eight adult SD rats were randomized into brain trauma+hemin group, brain trauma+normal saline group and sham-operated group, and in the former two groups, the rats were subjected to fluid percussion injury of the brain followed by intraperitoneal injections of 45 mg/100 mg hemin or saline accordingly. The rats in the sham-operated group received incision of the scalp and drilling on the skull only. The behavioral changes of the rats after the treatments were evaluated by testing the latency of head turning on a ramp. The permeability of the blood brain barrier (BBB) was assessed by measuring the brain tissue content of Evans blue injected into the tail vein, and the expression of HO-1 in the brain tissue was detected using immunohistochemistry with SP method. Results HO-1 expression in the brain tissue of heroin-treated rats (125.52±14.39) was significantly increased as compared with that of normal saline-treated rats (100.63±12.32) and sham-operated rats (79.37±12.89) (P<0.05). The latency of head turning on the ramp was significantly shorter in hemin-treated group (7.38±1.69 s) than in normal saline group (10.01±1.61 s,P<0.05). The permeability of the BBB was markedly decreased in heroin group. Conclusion HO-1 expression in the brain tissue may provide protection of central nervous system after brain trauma.