[Association of TLR3-1377C/T gene polymorphisms and expression with susceptibility to enterovirus 71 encephalitis in children].

OBJECTIVE: To investigate the association of gene polymorphisms of Toll-like receptor 3 (TLR3)-1377C/T and expression of TLR3 with the susceptibility to enterovirus 71 (EV71) encephalitis in children. METHODS: A total of 187 children with EV71 infection (59 children in the encephalitis group and 128 in the non-encephalitis group) and 232 children who underwent physical examination were enrolled in the case-control study. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the TLR3-1377C/T gene polymorphisms. ELISA was used to measure the serum level of TLR3. RESULTS: There were no significant differences in the genotype and allele frequencies of TLR3-1377C/T between the non-encephalitis group and the encephalitis group. Compared with the control group, the encephalitis group and the non-encephalitis group had significant increases in the serum level of TLR3 (P<0.05), and the non-encephalitis group had the highest level (P<0.05). The encephalitis group had a significantly higher EV71 viral load than the non-encephalitis group (P<0.01). The children aged <1 year or ≥1 year in the encephalitis group and the non-encephalitis group had significant increases in the serum level of TLR3 compared with their counterparts in the control group (P<0.05), and the children aged <1 year or ≥1 year in the non-encephalitis group had a significantly higher serum level of TLR3 than those in the encephalitis group (P<0.05). In the encephalitis group, the children aged ≥1 year had a significantly higher TLR3 concentration than those aged <1 year (P<0.05), and there were no significant differences in the TLR3 concentration between the children aged ≥1 year and <1 year in the non-encephalitis group and the control group. In the encephalitis group, the proportion of children aged <1 year was significantly higher than those aged ≥1 year (P<0.05). CONCLUSIONS: The TLR3-1377C/T gene polymorphisms are not significantly associated with the development of EV71 encephalitis. Low expression of TLR3 might weaken the inhibitory effect on virus replication and promote the development of EV71 encephalitis. The deficiency in the expression of TLR3 in serum after EV71 infection might be an important factor for the development of encephalitis in infants.

[Differences of apoptotic-regulating gene expression in the hippocampus in rats with different ages after status convulsion].

OBJECTIVE: To explore the molecular mechanism of brain protection against convulsive brain damage in premature brains by observing the changes of apoptotic-regulating genes of bcl-2 and c-Jun expression in the hippocampus in Wistar rats with different ages after status convulsion (SC). METHODS: SC was induced in infant Wistar rats (IRs) and adult Wistar rats (ARs) by intraperitoneal injection of lithium-pilocarpine. The rats were sacrificed at 3 hrs, 6 hrs, 12 hrs, 1 day, 3 days and 7 days after SC (n=8). Bcl-2 and c-Jun protein and mRNA levels were measured using immunocytochemistry, RT-PCR and in situ hybridization. RESULTS: c-Jun protein levels increased significantly at 3 hrs and reached the peak at 6 hrs after SC in both IRs and ARs compared to those in the normal control group (P<0.01). c-Jun protein levels started to decrease 12 hrs after SC in both IRs and ARs. The expression of c-Jun protein in IRs returned to the basal level 1 day after SC, while remained higher in ARs than in the normal control group by 7 days after SC. The expression of c-Jun protein in ARs was much higher than that in IRs from 6 hrs to 7 days after SC (P<0.05). c-Jun mRNA level was in parallel with the protein level as mentioned in IRs and ARs after SC. There were no changes observed in both bcl-2 protein and bcl-2 mRNA levels after SC in IRs and ARs. CONCLUSIONS: SC may induce an up-regulation of proapoptotic gene c-Jun in the hippocampus after SC, with a less strong extent and shorter duration in IRs compared to that in ARs. This might be one mechanism of brain protection against convulsive brain damage in IRs. The expression of bcl-2 remains unchanged after SC and is not affected by age in both IRs and ARs.

[Effect of duration of convulsion state on neuronal apoptosis and early apoptotic events in hippocampus of rats].

OBJECTIVE: To explore the influence of duration of convulsion state (SC) on neuronal apoptosis, mitochondrial membrane potential (Deltapsim) and cytochrome C (cyt C) release in hippocampus in Wistar rats after SC. METHODS: SC lasting for 30 minutes or 3 hours was induced by intraperitoneal injection of lithium chloride and pilocarpine. Rats were sacrificed at 3, 6, 12 hours and on 1 day after 30 minutes SC and at 3, 6 hours and on 1 day after 3 hours SC. The apoptosis, mitochondrial Deltapsim and intracellular cyt C were determined with flow cytometry, and the correlation with SC duration was compared. RESULTS: The proportion of apoptotic cells, the decrease in mitochondrial Deltapsim and the release of intracellular cyt C significantly changed at 30 minutes after SC. The peak level of apoptosis was seen at 12 th hour after SC and that of mitochondrial peaked at 6 th hour after SC in apoptosis and the two early apoptotic events, respectively. Compared with the same time point after 30 minutes SC, the levels of apoptosis and the two early apoptotic events after 3 hours SC were much higher. The neuronal apoptosis and the two early apoptotic events in hippocampus after SC showed positive correlation with the duration of SC in partial correlation analysis (all P<0.05). CONCLUSION: Severe seizure could induce the changes in neuronal apoptosis and the early apoptotic events in hippocampus after SC. The longer the duration of SC is, the more serious change in apoptosis and early apoptotic events are.