The Mechanism Of PARP-1/AIF Mediated Parthanatos Pathway In Striatum Demage Of Rat With Glutaric Aciduria

Objective In this study, Chronic glutaric acid(GA) subcutaneously administered to rats to established models of glutric aciduria type-I disease states, and PARP-1 inhibitor(PJ34)was given advance by intraperitoneal injection. Observe the microscopic pathology change and the protein expression of PARP-1 and AIF in corpus striatum, to explore the molecular mechanism of Parthanatos pathway in corpus striatum demage of neonatal rat with Glutaric acidemia, screening targets for clinical intervention, and the protect effect of PARP-1 inhibitor to striatal neurons,provide a theoretical basis for treatment, while providing new ideas to study the mechanisms of such single-gene genetic disease.Methods 1. Newborn male rats will be randomly divided into five groups in the next day of birth: normal control group(NS), low-dose group glutaric acid(LGA), high-dosegroup glutaric acid(HGA), low-dose group + protective agent(PARP-1 inhibitor)(LGA + PJ34) and high-dose + protection Group(HGA + PJ34). 2. These pups were subcutaneously administered with three injections of 5 μmol GA/g body weight in LGA group,10 μmol GA/g body weight in HGA group and 5 μmol NS/g body weight in NS group from postnatal day 4 to 23 at 7:30 am, 15:00 pm and 22:30 pm. Protective agents(PJ34) intraperitoneal injection every day by10 mg / kg 30 min before the first administration. The rats were killed by decapitation 12 h after the last injection. Body weights were measured 3 times per day and the mean weight of a day was recorded. 3. The change of microscopic pathology in corpus striatum was evaluated by HE staining, protein expression of PARP-1 and AIF were evaluated by Western bloting: after anesthesia by 10% chloral hydrate, the rats were decapitated and removal of the brain, striatal tissues were dissected on the ice, stored at –80°C freezer for protein extraction or fixed in 4% paraformaldehyde for hematoxylin and eosin(HE) staining.Results 1. The comparison of survival rate in different groups: 23 days after birth, rats in LGA group survival 8, the survival rate is 88.89%(8/9), but there are only 5 rats survival in HGA group, and the survival rate is only 21.74%(5/23), rats in HGA+PJ34 group live 7, the survival rate is 77.78%(7/9),and survival rate of rats in LGA+PJ34group and NS group is 100%. The survival rate of rats in HGA group are obviously lower than other groups, and the survival rate in 2 weeks after birth is higher,about 72.22% rats of this group are died in 2 weeks after birth. After 2 weeks of birth, the rats in HGA group have a lower mortality. 2. The comparison of weight in different groups: The weight of four days after birth in different groups have no significant differences, but as the delivery time goes on, the neonatal rat weight in groups of LGA and HGA are obviously lower than NS group and the PJ34 intervention group of corresponding concentration with GA, especially in HGA group. And 20 days after birth, the weight difference compared with NS group decreased. Compared the weight difference of rats 23 days after birthin each group, just the weight in HGA group obviously lower than NS group, and the difference decreased, the weight difference in other 4 groups have no significant difference. 3. The change of microscopic pathology observed by HE staining: In the groups of HGA, LGA, HGA+PJ34 and LGA+PJ34, interstitial edema, vacuolations, widened perivascular space of bilateral striatum were observed by HE staining, besides, chromatin concentration, karyorrhexis, disorder of neuron structure can be find in HGA group. 4. The protein expression lever of PARP-1 and AIF evaluated by Western blot: The protein level of PARP-1 and AIF were up-regulated in groups of HGA, LGA, HGA+PJ34 and LGA+PJ34, especially in HGA and LGA groups.Conclusions 1、Long-time chronic GA subcutaneous injection can increase the expression of PARP-1 and the release of AIF, and subsequently initiate the Parthanaos pathway, which may be involved in the GA-induced striatal lesion. 2、PARP-1 inhibitor-PJ34 can black the Parthanatos parthways by reducing the activity of PARP-1 and suppress the nuclear translocation of AIF, and protect the damage of striatal neurons induced by GA.