| Background: Perinatal asphyxia or neonatal asphyxia is the medical condition resultingfrom deprivation of oxygen to a newborn infant that lasts long enough during perinatal periodto cause physical harm, usually to the brain damage which is of most concern and perhaps theleast likely to quickly or completely heal.Perinatal asphyxia has a high incidence rate.According the epidemiological statistics, about920,000neonate deaths were caused byperinatal asphyxia each year. In addition to1.1million cases of abortion associated with thisdisease. In the more pronounced cases, more than100million cases, the infants will survive,but with damage to the brain manifested as either mental, such as developmental delay orintellectual disability, or physical, such as spasticity, cerebral palsy or epilepsy.Perinatal prolonged oxygen deficiency is a direct cause of neonatal hypoxic-ischemicbrain injury. In the induction of hypoxic-ischemic, a complex chain reaction is activated andeventually causes the death of neuronal cell and impairment of the central nervous system.During this process, The complement system plays a crucial negative role. In the hypoxic-ischemic condition, the activated complement system induce the inflammatory response andboost the synthesis and release of various cytokines, eventually cause varying degrees ofhypoxic-ischemic brain injury.High doses of human immunoglobulin G could reduce thehypoxic-ischemic brain injury byeliminating harmful complement fragment, blockingcomplement pathway and inhibiting of the inflammatory response. Using mouse transientbrain artery blockage model, it is observed that given the high dose of H-IgG can significantlyreduce the size of the cerebral infarction area and subsequent dysfunction of the nervous system, and approved active complement C3b fragment has deposited largely in the area ofinjured brain.Aim: In this study, we simulated the mechanism of neonatal HI brain injury by settingup a HI brain injury model using7days newborn rat. Our purpose is to assess the cerebralprotective effects of HI brain injury of H-IgG,explore the potential mechanisms and providenew therapeutic options and the theoretical basis for the clinical treatment of neonatalhypoxic-ischemic brain injury.Methods: This experiment was established by the focal of Wistar rat pups hypoxicischemic brain damage (Hypoxic ischemic brain injury). Choose7days after the birth ofWistar rat pups, under anesthesia double ligation of left common carotid artery, with two linesbetween the common carotid artery ligation of cut. After1hours of recovery, put them in aairtight Hypoxic tank with continuous8%oxygen for1or2hours. Then remove the back tothe female rats. Establish the entire modeling process, monitor body temperature to keep it at37.0±0.5°C. Experimental groups:(1) sham operation group,1hour hypoxic-ischemicgroup, two hours hypoxic-ischemic group;(2)sham operation group, hypoxic ischemic group,solvent group or vehicle group, high doses of H-IgG group(2.0g/kg);(3) sham operationgroup, pretreatment modeling vehicle group, pretreatment h-IgG group, one hour afterhypoxic-ischemic given vehicle group, one hour after hypoxic-ischemic given high-dose H-IgG group;(4) the sham operation group, vehicle group, high dose of H-IgG group (2.0g/kg),middle dose of H-IgG group (1.0g/kg), low dose H-IgG group (0.5g/kg). Histologicalevaluation of brain sample of different recovery time after HI was observed by H&E stain.Evaluation of the protective effect of H-IgG on hypoxic ischemic brain damage by TTCstaining was used to assess the degree of brain injury. Behavioral research: for acute braininjury, subacute and chronic brain function evaluation was estimated by nerological scale andthe following experiments:(1) the righting reflect experiment;(2) wire hanging test;(3) footfault test. Given IgG western blot, complement C3in serum and brain tissue level changes in the pups experienced hypoxic-ischemic brain injury is detected, as well as to assess the levelof complement C3in serum and brain tissue in rats after given IgG, and compared with thosein the control group and sham operation group. Through the immunochemistry, visualobservation of complement C3distribution in the brain tissue in the pups with hypoxicischemic brain damage in neonatal rats, as well as the eradication of complement C3in thebrain tissue after given H-IgG treatment, and the results were compared with the controlgroup.Results: Postnatal7days pups neonatal rats were given1or2hours of hypoxia inpermanent ligation of carotid artery. Through TTC staining evaluated the extend of braindamage. The results showed that2-hours hypoxia group can establish a relatively stableneonatal rat pups hypoxic-ischemic brain injury model, while1hour of hypoxia groupshowed larger variability, There were significant differences between the two groups(X2=20.417, p=0.000, B in Figure4.1). Given high doses of H-IgG treatment on hypoxic-ischemic brain damage in newborn rat pups, according to the result of group compared withthe control group, can significantly reduce the infarct volume and brain edema.(P<0.01,Student T test)(Figure4.3.1). We compare the different time points groups treated with H-IgG. Compared to the control group, given treatment of H-IgG1hour before or after injuryboth can significantly reduce the infarct volume and brain edema (p<0.01, Student T Test).There was no significant difference between the two groups (p>0.05, Student T Test)(asshown in Figure4.3.2).Conclusions:(1)Using our rat model, we observed the minimum time of causing hypoxia hypoxic-ischemic brain injury is1hour.(2)The cerebral protective effects of HI cerebral injury of H-IgG in newborn rat:1. The dose-dependence of cerebral protective effects of H-IgG: High doses of H-IgG(2.0g/kg) can obviously protect cerebrum away from HI cerebral injury in newborn rat.Moderate doses of H-IgG(1.0g/kg) has certain cerebral protective effects, but it’s not assignificant as high doses of H-IgG.2. The time-dependence of cerebral protective effects of H-IgG: Administrations all havethe cerebral protective effects in one hour before and after hypoxia.(3)H-IgG has the cerebral protective effects not only in acute HI brain injury, but also insignificant improvement in the growth and developmental disorders in7days newborn rat.(4)Cleaning complement C3b and Inhibiting the inflammatory response maybe are theway that H-IgG’s cerebral protective effects of HI brain injury in newborn rat model.In a word, our study testified high dose of H-IgG has significant cerebral protectiveeffects in7days newborn rat with HI brain impairment. It provided a new way of thetreatment of neonatal HI brain injury and related diseases. |
PDF Full Text Request