A Study On The Change Of Myelin Protein Lipoprotein (PLP) After PCC And MCC In Rats

Partâ… A study on the change of myelin protein lipoprotein(PLP) after PCC and MCC in rats[Objective]:To establish the model of pure cerebral concussion (PCC) and multiple cerebral concussion (MCC) in rats, observe the changes of the expressing of PLP post-PCC and post-MCC.To explore difference between PCC and MCC. [Method]:The PCC or MCC model was.duplicated by using a metallic pendulum -striker concussive device.72 female and male Sprague-Dawley rats were randomly divided into tweleve groups:PCC1d.,2d,4d,8d,16d,24d group and MCCld,2d,4d,8d,16d,24d group (n=6,in each group). One control was used (n=6). Using the immunostaining of streptavidin-peroxidase (S-P) method and image analysis system to detect optical density value of PLP in the following areas, that is the septal area section, the hippocampus section and brainstem section. [Result]:1. PLP was expressed widely in the brain of rat.1. PCC. In prefrontal-septum section, the value of optical density (VOD) of PLP(+) substance is higher in F3 (1 d after injury), P1 (8d after injury), P3 (4d after injury), P6 (4d after injury), but is lower in F2 (8d after injury), P4 (8d after injury) than that in related-area at related-time in control group, there is no difference in other area at differnet time.In the hippocampus section, most areas showed reduced expression of PLP, but no statistical significance. At day24 after injury, PLP expression had reached the same level as control except that the VOD was still lower in P3 (4,16 days after injury), f (1,4,16 days after injury) than control (p<0.05). The expression of PLP in most areas in sagittal section of brainstem is similar as that in hippocampus section. Among them, the PLP in Gr area (1,4,8,16,24 days after injury) is reduced significantly, compared with control (P<0.05).in contrast, there was an increase in LDTg (16 day after injury) and Rnl (16 day after injury), Rn2 (4 days after injury) (P<0.05).2. In the coronal section of prefrontal-septum, most areas expressed fewer PLP, some of them did not still reach the level as control. Among them, the PLP expression in F1 (1,24 days after injury), F2 (1,2,4,16 days after injury), P4 (2,4,16, days after injury), P5 (4,8,16 days after injury), striatum (CPu) (1,2,16 days after injury) is lower than control (p<0.05).In coranal section of hippocampus, There was an minor upregulation trend of PLP in 2 days after injury, and a downregulation afterward, but both no stantistical significance. Among them, there were obvious upregulation in P2 (1 day after injury), P3 (2 days after injury), conpared with control (P<0.05).In sagittal section of brainstem, generally, there was a downregulation trend of PLP, but not reach stantistical level, compared with control. Among them, the PLP expression in Gr (1,2,4,8,16,24 days after injury), Pnl (8,16 days)is lower than control (P<0.05). in contrst The PLP expression in IC (1 day after injury), LDTg (16 days after injury), Mve (1day after injury) Rn (1day),10 (24 days after injury) were upregulated (P<0.05).3.In coronal section of prefrontal-septum, F1, F2, F3, F4, P1, P3, amygdaloid nucleus, P4, P5, P6, Cpu all showed obviously different in PLP expression except for P2, corpus callosum (cc), anterior commissure. Furthermore, the areas expressing lower PLP were more after MCC than that after PCC.In coranal section of hippocampus, generally, PLP expression in MCC group was higher than that in PCC group in 4 days after injury, But it is opposite at 24 day after injure. Particularly, in MCC group, F1 (2 days after injury), F2 (1 day after injure), F3 (2days after injury), F4 (1,8 days after injury), P1 (1 day after injury), P2 (1 day after injury), P3 (2 days after injury), P4 (2 days after injury), hippocampus (4 days after injury), thalamus (2 days after injury), stria medullaris of the thalamus (sm) (16 days after injury) expressed more PLP than these areas in PCC group, except for fornix (f). The PLP expression in cc is fewer in MCC than that in PCC at day2 after injury. In sagittal section of brainstem, general differenc of PLP expression was not obvious between MCC and PCC. PLP in IC (1 day), LDTg(24 days), Mve (1day), Rn2 (1 day),IO (24 days) was higher in MCC than that in PCC, but that in Gr (2 days), Pn1 (16 days), Pn2 (4 days),IO (1 day) si fewer in MCC than that in PCC.[Conclusions]:1. PLP is expressed widely in brain of rat, in rat cerebral concussion model, there are obvious changes of expression in many areas between PCC or MCC and control and time-depandent change after injury, especially, in MCC group.2. After PCC, the PLP expression difference in septum, hippocampus and brainstem between PCC and control is not obvious, but after MCC, especially in most areas of prefrontal-septum coranal section, PLP is downregulated in MCC group, and the area expressing significantly lower PLP level are more in MCC than in PCC. The persistent time is very long, the PLP in some areas can not reach the level as control at day24 after injury.Keywords:pure cerebral concussion multiple cerebral concussion myelin protein lipoproteinPartâ…¡A study on the change of cortex fiber's quantity after PCC and MCC in rats[Objective]:To establish the model of pure cerebral concussion (PCC) and multiple cerebral concussion (MCC) in rats, observe the changes of the myelinated nerve fiber post-PCC and post-MCC.To explore difference between PCC and MCC. [Method]:The PCC or MCC model was.duplicated by using a metallic pendulum-striker concussive device.72 female and male Sprague - Dawley rats were randomly divided into tweleve groups:PCCld,2d,4d,8d,16d,24d group and MCCld,2d,4d,8d,16d,24d group (n=6,in each group). One control was used (n=6). Using the immunostaining of streptavidin-peroxidase (S-P) method and observe the changes of the myelinated nerve fiber in the following areas, that is theseptal area section and the hippocampus section. [Result]:1. In PCC group, the quantity grade of myelinated nerve fiber in F4 area (2 days after injury) but not in F1, F2, F3 (1,2,4,8,16,24 days after injury), F4 (1,4,8,16,24 days) of cortical molecular layer in prefrontal-septum section, and in F1 (2 days after injury), F2 (1,8,16 days after injury), F3 (1,2 days after injury), F4 (2 days after injury) but not in F1 (1,4,8,16,24 days after injury), F2 (2,4,24 days after injury), F3 (4,8,16,24 days after injury), F4 (1,4,8,16,24 day after injury) of cortical molecular layer in hippocampus section were lower significantly than related-area and related-time in control group.2. In MCC group, the quantity grade of myelinated nerve fiber in F1 (1,8 days after injury), F2 (4,24days after injury), F3 (2,4 days after injury), F4 (2 days after injury) but not in F1 (2,4,16,24 days after injury), F2 (1,2,8,16 days after injury), F3 (1,8,16,24 days after injury), F4 (1,4,8,16,24 day after injury) of cortical molecular layer in prefrontal-septum section, and in F1 area (16 days after injury),F2 area (4 days after injury) but not in F1(1,2,4,8,24 day), F2(1,2,8,16,24 day) F3,F4 (1,2,4,8,16,24 days after injury), of cortical molecular layer in hippocampus section were lower significantly than related-area and related-time in control group.[Conclusions]:In rat cerebral concussion model,MCC led to more intense decrease of the quantity grade of myelinated nerve fiber in Cortical molecular layer than that by PCC in prefrontal-septum section but the opposite effect occurred in hippocampus section. Among the whole cortical molecular layer the number of myelinated nerve fiber in Fl area is the most.