ABSTRACT
In previous study,glutaric acid (GA) induced apoptosis of primary striatal neuron in vitro.In order to investigate the neurotoxic effects of GA on neonatal rat corpus striatum and the possible mechanism,34 male pups were randomly assigned to NS group,low dose GA (LGA,5 μmol GA/g body weight) group and high dose GA (HGA,10 μmol GA/g body weight) group.These pups were subcutaneously administered with three injections from postnatal day 3 to 22 at 7:30 am,15:00 pm and 22:30 pm and killed 12 h after the last injection.Microscopic pathology in corpus striatum was evaluated by HE staining.The apoptotic cells were identified by TUNEL staining.The transcript levels of caspase-3,8,9,Bax,Bcl-2 were detected by using real-time PCR and the protein levels of procaspase-3 and the active fraction were evaluated by Westem blotting.In LGA and HGA groups,ventricle collapse,cortical atrophy by a macroscope and interstitial edema,vacuolations,widened perivascular space of bilateral striatum by a microscope were observed.TUNEL assay revealed that the apoptotic cells were increased in LGA and HGA groups.The transcript of caspase-3 was up-regulated to 2.5 fold,accompanied by the up-regulation of caspase-9,Bax and down-regulation of Bcl-2.The protein levels ofprocaspase-3 and the active fraction were up-regulated in LGA and HGA groups.The rat model for GA Ⅰ showed mitochondrial apoptotic pathway may be involved in the GA-induced striatal lesion.Further studies should be taken to investigate the underlying mechanisms.
ABSTRACT
Methylmalonic aciduria (MMA) is a common inherited autosomal recessive disorder resulting from defects in the enzyme methylmalonyl CoA mutase (MCM,mut complementation group) or in the synthesis of the MCM cofactor adenosylcobalamin (cbl complementation groups).The defects in the mut complementation group accounts for the largest number of patients with isolated MMA.At least 200 mutations in the MUT gene on chromosome 6p12 have been identified in MMA patients until now.This study aimed to investigate the clinical characteristics of MMA and genomic variations in the MUT gene of Chinese patients.Genomic DNA was extracted from 18 patients who were diagnosed as having isolated MMA by gas chromatography/mass spectrometry (GC-MS),and from some of their parents as well.Amplification and direct sequencing of the MUT coding regions (exon 2-13) and their adjacent intronic consensus splice sites were performed in order to identify the disease causing mutations.In this group,six novel mutations in the MUT gene,c.424A＞G (p.T142A),c.786T＞G (p.S262R),c.808G＞C(p.G270R),c.1323_1324insA,c.1445-1G＞A and c.1676+77A＞C were identified.p.T142A and p.G270R were respectively detected at a heterozygous level in one patient.Two previously reported mutations,c.682C＞T (p.R228X) and c.323G＞A (p.R108H) were also found in this study.In addition,six previously described single nucleotide polymorphism (SNP),c.636A＞G (p.K212K),c.1495G＞A(p.A499T),c.1595A＞G (p.H532R),c.1992G＞A (p.A664A),c.2011G＞A (p.V671I) and c.1677-53A＞Gwere identified.In this study,we updated the spectrum of MUT mutations and identified the main MMA-causing mutations in Chinese MMA patients.