ABSTRACT
Objective To investigate the protective effect of caffeine citrate on white matter damage in 2-day-old neonatal rats induced by postnatal infection.Methods Forty-eight 2-day-old SD rats were randomly divided into the control group (group A,n =16),lipopolysaccharide(LPS) infection group (group B,n =16),and caffeine citrate intervention group (group C,n =16) according to the random table method.The newborn rats of group B and C were continuously injected LPS 0.6 mg/kg intraperitoneally for 5 days from 2 days old,and the newborn rats of group A were continuously injected by an equal volume of 9 g/L saline intraperitoneally.Group C was continuously injected by caffeine citrate 10 mg/kg intraperitoneally for 7 days from 4 days old;equal volume of 9 g/L saline was injected into group A and B for 7 days continuously.At 12 days old,8 rats of each group were sacrificed randomly to evaluate the expression of myelin basic protein(MBP) subcortical white matter by immunohistochemical method.Both sides of hippocampus of the rest 8 rats of each group were taken out in ice surface rapidly.The left hippocampus was used to detect the expression of MBP and Caspase-3 by Western blot method,and the right hippocampus was used to evaluate the MBP and Caspase-3 protein level by quantitative real-time PCR(qPCR) method.Results The mean integral optical density (IOD) of subcortical MBP positive expression in group A,group B and group C were 132.64 ± 1.94,102.43 ± 2.12,114.25 ± 2.04,and the difference was statistically significant among 3 groups (F =22.912,P ＜ 0.05).The relative expression levels of MBP mRNA of 3 groups in hippocampus were 0.79 ± 0.01,0.39 ± 0.03,0.55 ± 0.02,and the difference was statistically significant among 3 groups (F =18.584,P ＜ 0.05).The relative expression levels of MBP protein of 3 groups in hippocampus were 0.64 ± 0.03,0.31 ± 0.03,0.51 ± 0.05,and the difference was statistically significant among 3 groups (F =25.780,P ＜ 0.05).The relative expression levels of Caspase-3 mRNA of 3 groups in hippocampus were 0.34 ± 0.02,0.74 ± 0.03,0.57 ± 0.04,and the difference was statistically significant among 3 groups (F =6.105,P ＜ 0.05).The relative expression of Caspase-3 protein of 3 groups in hippocampus were 0.11 ± 0.03,0.36 ± 0.02,0.23 ± 0.03,and the difference was statistically significant among 3 groups (F =40.541,P ＜ 0.05).Conclusions Caffeine citrate has showed protective effect on white matter damage in neonatal rats of 2 days old induced by postnatal infection.The mechanism may be related to inhibition of inflammatory response and reducing apoptosis.