EPO And EPOR MRNA Expression In Neonatal Rats With White Matter Damage Associated With Intrauterine Inflammation And The Therapeutic Effect Of RhEPO

Objective:To establish animal models of intrauterine inflammation by intraperitoneal injection of lipopolysaccharide. To investigate the rencent and long-term neuroprotective effect of rh EPO on neonatal rats with white matter damage associated with intrauterine inflammation by detecting the expression of EPO/EPOR m RNA 、CD68、GFAP、 MBP and evaluating the neurobehavior in order to provide basis for the clinical using of rh EPO.Methods30 pregnant wistar rats(gestational age 15 days) were randomly divided into the experimental group and control group. The rats in the experimental group were intraperitoneal-injected of LPS(300μg/kg) to make cerebral white matter lesions. While rats in the control group were intraperitoneal injectioned with equivalent saline(1m L/kg)instead. 30 newborn rats were randomly selected from two groups respectively. Their brain tissue was taken out by 4% formaldehyde perfusing. White matter damage in left brain tissue was detected by hematoxylin eosin(HE) staining and the level of EPO and EPOR m RNA were detected by real time fluorescent quantitative RT-PCR. 60 neonatal rats were chosen from the remain rats in the experiment group and were randomly divided into LPS+rh EPO group(n=30) and LPS+NS group(n=30) according to the different processing methods which were respectively intraperitoneal injected of rh EPO(5000IU/kg) or saline 1m L/kg immediately after birth. 60 neonatal rats were chosen from the remain rats in the control group and were randomly divided into NS+rh EPO group(n=30) and NS+NS group(n=30). The cerebral white matter injury were evaluated by HE staining and levels of CD68, GFAP, MBP were detected with immunofluorescence 3 and7 days after birth. Assessments of nerve behavior were taken 2 weeks after birth.Result1. HE staining showed periventricular white matter was lightly stained with sparse structure and reticular change in neonatal rats injected intraperitoneally with LPS while the control group structure were normal.2. The expression of EPO m RNA and EPOR m RNA in the corpus callosum was significantly higher than that of injected with physiological saline(P < 0.01).3. HE staining showed white matter lesions was less in LPS+rh EPO group than that in LPS+NS group 3 and 7 days after birth while NS+rh EPO group and NS+NS group had no cerebral white matter lesions.4. The expression of CD68 in LPS+rh EPO group,NS+ rh EPO group、NS+NS group significantly decreased comparing with LPS+NS group(F=7.456,P < 0.01) 3 days after birth. The expression of GFAP in LPS+rh EPO group, NS+ rh EPO group、NS+NS group was lower than that in LPS+NS group(F=5.121,P < 0.01) 7 days after birth. Meanwhile,the expressions of MBP were not statistically different between the groups3( F=2.628)and 7 days(F=1.425)after birth.5. No significant difference were found between LPS+rh EPO group with other groups in evaluation of long-term neural development. The values of F for the pen field test, suspension test, teep hill test, the resistance to capture test are 2.09、0.53、0.11、0.37 seprately.Conclusion1. The expression of EPO m RNA and EPOR m RNA is high in neonatal rats with white matter damage.2. rh EPO displays neuroprotective effect on cerebral white matter lesions in the neonatal rats by inhibiting microglia and astrocyte activation in a short time.3. The long-term effort of rh EPO on cerebral white matter lesions remains unknown.