ABSTRACT
Objective:To investigate the Effect of madecassoside (MC) on hippocampal NR2B expression and cognitive function following traumatic brain injury (TBI).Methods:One hundred and sixteen SD rats were provided by the experimental animal center of Medical College in Xi′an Jiao Tong University. Rats were randomly divided into four groups ( n=29) as following: Control group (Con group), TBI group, MC treated TBI rats group (TBI+ MC group) and MC treated control rats group (Con+ MC group). NR2B protein levels in hippocampus were detected by Western-blot at 12 h, 1 d, 3 d, 7 d, 14 d and 21 d post trauma. Hippocampal NR2B positive cells were studied by immunohistochemical (IHC) staining at 21 d post trauma. Cognitive functions of rats were evaluated by Morris water maze (MWM) test from 21 d to 25 d post trauma. Results:Expression of hippocampal NR2B in TBI group at 12 h, 1 d and 3 d post injury were 3.31±0.28, 2.17±0.31 and 1.96±0.31, which presented statistical difference among the three time-points ( P<0.05) and were significantly increased compared to Con group ( P<0.05). However, there was no difference of NR2B level between TBI group (0.93±0.13) and Con group ( P>0.05) at 7 d post injury. In addition, NR2B expression in TBI group at 14 d and 21 d post injury were 0.45±0.04 and 0.21±0.04, which were much lower than that in Con group. IHC staining revealed that the number of hippocampal NR2B positive cells in TBI group (33.26±9.71) were lesser than that of Con group (86.62±17.05). Increased Escape latency, decreased platform crossing times and target quadrant duration were found in TBI group compared with Con group ( P<0.05). Hippocampal NR2B expression in TBI+ MC group at 12 h, 1 d and 3 d post injury were 2.37±0.34, 1.38±0.22 and 1.14±0.16. Difference among the three time-points exhibited statistical significance ( P<0.05). In addition, they were much lower than that in TBI group at the same time-points ( P<0.05), but no difference was found between TBI+ MC group (0.97±0.06) and TBI group at 7 d post injury ( P>0.05). Moreover, NR2B expression in TBI+ MC group at 14 d and 21 d post injury were 0.86±0.08 and 0.52±0.06, which were much higher than that in TBI group ( P<0.05). IHC staining showed the number of hippocampal NR2B positive cells in TBI+ MC group (69.08±12.24) were much more than that of TBI group (33.26±9.71). A decrease of escape latency, an increase of platform crossing times and target quadrant duration were found in TBI+ MC group compared to TBI group ( P<0.05). Conclusion:MC treatment could inhibit the up-regulation of NR2B in hippocampus at early period of TBI and prevent the down-regulation of NR2B at advanced stage of TBI, which led to a remarkable improvement for the cognitive dysfunction caused by TBI.
ABSTRACT
Objectives It was constructed that the replication defective adenoviral vectors carried the short hairpin sequences of mouse SCP2.And we will make a further study of mechanism between SCP2 gene and cholesterol stone in gallbladder.Methods The short hairpin sequences of mouse SCP2 were cloned by two-step PCR,and connected together with the plasmid pDC312.The Admax Adenoviral Vector System was used to generate the replication defective adenoviral vectors,which were purified by CsCl method.The processes of TCID50 were applied to detect the titers of the adenoviral vectors.Furthermore,Protein levels of SCP2 were determined by Western blot analysis,and the levels of SCP2、CYP7A1、HMGCR mRNA from the hepa1-6 cell of mouse were measured by the usage of RT-PCR.Results SCP2mRNA and SCP2 protein were down-regulated by the replication defective adenoviral vectors carried the SCP2-shRNA.With the decreasing SCP2mRNA,the levels of HMGCRmRNA were down-regulated at same the time,while CYP7A1mRNA were up-regulated.Conclusions The replication defective adenoviral vectors carried SCP2-shRNA were constructed successfully.The lower levels of SCP2 could affect the activities of HMG-CoA reductase and CYP7-a enzyme,which caused the variations of cholesterol metabolism and then decreased the formation of cholesterol stone.