Changes Of Per1 And Cry1 Genes' Expression In HIBD Neonatal Rat Pineal Gland

Background Neonatal hypoxic-ischemic brain damage(HIBD) is induced by perinatal oxygen deficiency. The survivals may show disorders in psychomotor development,sleep-wake cycle and hormone secretion,etc. The mammalian pineal gland is considered as a neuro-endocrine translator. The basic circadian structure is the intracellular circadian oscillator, which is made up of core clock genes. These genes and their expression products form interlocked feedback loops of transcription / translation, two significant genes among which are Per1 and Cry1. However, Studies about circadian disturbance in HIBD are so few that the mechanism of circadian disorders in HIBD is indefinite.Objective To explore the effects of clock genes on circadian disorder in hypoxic-ischemic brain damage (HIBD) by comparing the level of PER1,CRY1 synthesis and the expression of Per1 mRNA, Cry1 mRNA in HIBD group and control group of neonatal rat pineal gland .Methods 7-day-old Sprague-Dawley (SD) rats were randomly divided into 2 groups (36 pups each). HIBD models were set up according to modified Levine euthanized 0,2,12,24,36,48 hours afterwards. Semi-quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)analysis was used to measure the expression profiles of Per1 mRNA and Cry1 mRNA and Western Blotting for PER1,CRY1 protein in rat pineal gland,comparing the differences between two groups。Results Comparing with the control group:1,The levels of Per1 mRNA in HIBD group displayed significantly higher than those of the control group at 24 h,36 h, and 48 h(P<0.05) while no statistically significant differences at 0 h, 2 h, 12 h (P>0.05). The levels of Per1 mRNA in HIBD begin to rise at 24 h, arrive to the peak at 36 h and continue to 48 h. 2,The levels of Cry1 mRNA in HIBD group displayed significantly higher than those of the control group at 12 h,24 h and 36 h(P<0.05) while no statistically significant differences at 0 h, 2 h, 48 h(P>0.05). The levels of Cry1 mRNA in HIBD begin to rise at 12 h, arrive to the peak at 24 h and continue to 36 h. 3,The levels of PER1 protein in HIBD group have overcome those of the control group at 36 h (P<0.05),and there are no statistically significant differences at 0 h, 2 h, 12h ,24 h and 48 h (P>0.05).4,The levels of CRY1 protein in HIBD group have overcome those of the control group at 12 h ,24 h and 36 h(P<0.05),and there are no statistically significant differences at 0 hour,2 hour and 48 hour(P>0.05). The levels of CRY1 protein in HIBD begin to rise at 2 h, arrive to the peak at 24 h and descend to normal at 36 h.Conclusion HIBD indeed affects the level of PER1,CRY1 protein and the expression of Per1 mRNA, Cry1 mRNA in the neonatal rat pineal gland, the disorder of biological clock may play important roles in the mechanism of HIBD.