Establishment of a Parkinson’s disease model in rats via striatal one-site double injection Feasibility observation

BACKGROUND： To date, many 6-hydroxydopamine （6-OHDA）-lesioned rat models have been established by injecting 6-OHDA into two or more sites in the substantia nigra pars compacta, striatum or median forebrain bundle. The success rate of models established by this method is satisfactory, but it can raise the death rate, and is elaborate and tedious to perform. OBJECTIVE： To observe the difference between injections of 6-OHDA into the striatum from one site and two sites, and to explore the feasibility of establishing Parkinson＇s disease rat models via striatal one-site double injection. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment based on a modeling comparison was performed at the Pharmacology Laboratory of Traditional Chinese Medicine, Academy of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine between August 2005 and April 2006. MATERIALS： A total of 46 male Wistar rats were purchased from Beijing Weitong Lihua Experimental Animal Technical Co., Ltd., China. 6-OHDA hydrogen bromide was sourced from Sigma Co., Ltd., USA. METHODS： All 46 rats were randomized to three groups： one-site injection （n = 18）, two-site injection （n = 18）, and control （n = 10）. Lesions in rat brains were established by infusing 5 μg 6-OHDA into the striatum at the following coordinates： anteroposterior （AP） 1.0 mm, mediolateral （ML） 2.7 mm, dorsoventral （DV）-5.2 or-6.0 mm for the one-site injection group, and AP 1.0 mm, ML 2.5 mm, DV -4.5 mm/AP-0.4 mm, ML 3.5 mm, DV-4.5 mm for the two-site injection group, respectively. Rats in the control group were injected with the same volume of 0.01% ascorbic acid as above. MAIN OUTCOME MEASURES： Tyrosine hydroxylase-positive neurons were detected by immunohistochemistry. Success rates of PD models established by one-site and two-site injection techniques were examined. RESULTS： One rat died in the one-site injection group and four in the two-site injection group. Thus behavioral testing was performed on 31 rats. There was no significant difference in the success rate of PD model establishment between one-site injection and two-site injection groups [82% （14/17） vs. 86% （12/14）, P 〉 0.05]. The numbers of tyrosine hydroxylase -positive neurons in one-site injection and two-site injection groups were not significantly different （ P 〉 0.05）, but they were significantly lower than in the control group（P 〈 0.01 ）. CONCLUSION： A Parkinson＇s disease model can be established in rats via striatal one-site double injection.

Construction of a model of autologous blood intracerebral hemorrhage in rats with a double injection and double needle withdrawal and the characteristics of the operative technique

BACKGROUND ： Experimental animal models of intracerebral hemorrhag （ICH） are greatly needed, so the process of establishment should be ideal in hematoma formation and easy to operate. OBJECTIVE ： To construct model of ICH in rats with double injection of autologous blood taken from the cut tail cut and double withdrawal of the needle （shortened as two-step injection model）, and compare with those induced by single and double injections. DESIGN ： A randomized controlled tria SETTING： Department of Neurology, General Hospital of Military Area Command of Chinese PLA. MATERIALS： Thirty male Wistar rats of 10 to 12 months, weighing （400±25） g, provided by the Experimental Center of Medical Animals, General Hospital of Shenyang Military Area Command of Chinese PLA, were divided randomly into 3 groups with 10 rats in each group： two-step injection group, single injection group, double injection group. METHODS ： The experiment was carried out in the Department of Neurology, General Hospital of Military Area Command of Chinese PLA from March to June in 2004. Autologous blood ICH model in rats were established as follows： In the two-step injection group, 50 μL unclotted autologous blood was taken from the rat tail cut, then injected with microsyringe into the caudate nucleus, 10 μL injected at first, paused for 2 minutes, and then the rest 40 μL injected slowly and continuously within 2 minutes. After the injection, the needle was kept immovable for about 4 minutes, withdrawn 2.0 mm, again kept immovable for about 4 minute, and then removed wholly at a slow speed. In the single injection group, 50 μL unclotted tail blood was injected slowly and continuously all within 2 minutes and the needle was slowly removed;（4） In the double injection group, 10 mL blood was injected at first, paused for 2 minutes, the rest 40 μL injected evenly within 2 minutes, and then the needle was withdrawn slowly and uninterruptedly. Neurologic findings were scored in accordance with Longa＇s five-point scale （0-4 scores, the higher the score, the severer the neurological dysfunction）. The rats were killed to remove and sections were prepared, the morphological features of hematomas were grossly observed, the maximal diameter and size of hematomas in each slice were measured with the imaging analytical system, and the volume was calculated. Meanwhile, the conveniences of the techniques were compared. MAIN OUTCOME MEASURES： The morphological features and volume of hematomas, neurologic deficit score （NDS）, and the convenience of the techniques were compared. RESULTS： All the 30 rats were involved in the analysis of results without deletion. （1） Results of the morphological observation of volume of hematoma： In the two-step injection group, hematomas located in the right caudate nucleus area regularly in circular or analogously circular shape in each slice. The formation rate of hematomas in the single injection group and double injection group were lower than those in the two-step injection group [60% （6/10）, 80% （8/10）, 100% （10/10）, P〈 0.01, 0.05]. The volume of hematomas in the single injection group and double injection group were smaller than those in the two-step injection group [（28.5±14.8）, （33.4±7.4）, （41.6±3.9） mm3, P〈 0.01, 0.05]. （2） NDS results： The NDS scores in the single injection group and double injection group were smaller than that in the two-step injection group （0.90±0.83, 1.30±0.78, 1.90±0.57, P〈 0.05）. （3）Comparison of the convenience of the techniques： The double injection method allowed generating reproducible hematomas in rats with shortcomings that it needed autologous arterial blood from femoral artery, and precision instruments such as microinfusion pump. The two-step injection injected fresh unclotting blood taken directly from the tail cut with microsyringe into the rat brain, and it has the advantages of easy operation, no influence on the activity of thrombase, shorter duration for model establishment, and higher rate of hematoma formation, which could generate ideal and economical models of ICH. The two-step injection induced hemotoma regularly in circular or analogously circular shape in each slice, but those induced by single and double injections were mostly in strip or fusiform shapes and extending along the needle tracks or into the ventricle or subarachnoid space. CONCLUSION ： The autologous blood ICH model induced by the two-step injection method is a reproducible and reliable one in regular shape, which is better than those induced by double and single injections.

Photo-sensitive characteristics of negative resistance turn-around occurring in SIPTH

Influences of light irradiation on the negative resistance turn-around characteristics of static induction photosensitive thyristor （SIPTH） have been experimentally and theoretically studied. As the gate current of SIPTH is increased by the light irradiation, the potential barrier in the channel is reduced due to the increase in voltage drop across the gate series resistance. Therefore, SIPTH can be quickly switched from the blocking state to the conducting state by relatively low anode voltage. The optimal matching relation for controlling anode conducting voltage of SIPTH by light irradiation has also been represented.