The intervention of baicalin on acute brain injury induced by aconitine in rats and its mechanism / 中国中西医结合急救杂志

ABSTRACT

Objective To investigate the interference effect of baicalin on acute brain injury induced by aconitine in rats and its mechanism. Methods A total of 200 Sprague-Dawley(SD)rats were randomly divided into five groupsnormal control,baicalin control,aconitine poisoning,baicalin 15 mg/kg intervention and baicalin 30 mg/kg intervention groups(each,n=40). Aconitine(20μg/kg)was given via tail vein in aconitine poisoning group. The rats in the normal control group and baicalin control group were respectively injected with saline 2 mL/kg and baicalin 30 mg/kg via tail vein. The aconitine poisoning rats were given with baicalin at the dose of 15 mg/kg and 30 mg/kg respectively in the low and high dose baicalin intervention groups within 2-3 minutes after injection of aconitine. Rats in all groups in the study were anesthetized and sacrificed at 1,6,12,24 hours after various agents were respectively given in the groups,the rat cerebral cortex samples were collected,the histological changes in normal and baicalin control groups and pathological changes of the aconitine poisoning rats were observed,the levels of glutamate(Glu),aspartate(Asp),γ-aminobutyric acid(GABA),glycine(Gly)were detected and the apoptotic cells were determined at the above time points. Results Compared with the normal control group,the aconitine poisoning group had significantly higher levels of excitatory amino acids Glu and Asp and the number of apoptotic neurons. After exposure to aconitine for 1 hour, the levels of inhibitory amino acids of GABA and Gly were markedly decreased in the rat cortex in the poisoning group compared to the normal control group(both P<0.05),at 6 hours and 12 hours they were significantly increased and after 24 h,they began to decline,but still maintained at relatively high levels. Compared with the aconitine poisoning group, after baicalin intervention for 1 hour,in the 15 mg/kg and 30 mg/kg baicalin intervention groups,the levels of Glu and Asp were markedly decreased〔Glu(μmol/L)309.39±14.59,307.22±23.69 vs. 370.46±40.31,Asp(μmol/L)143.43±8.36,129.12±4.86 vs. 222.97±6.26〕,while the levels of GABA and Gly were increased〔GABA(μmol/L)55.91±4.76,59.61±13.11 vs. 32.05±2.20,Gly(μmol/L)32.33±1.85,33.90±0.66 vs. 21.96±4.75〕,and the number of neuronal apoptosis was obviously decreased(cell/mm218.65±4.10,14.80±1.89 vs. 58.15±3.68,both P<0.05). Under microscope and electron microscope,the pathological and ultrastructural changes indicated that the aconitine poisoning group had the most marked cerebral cortex damage at 12 hours after poisoning,while the two baicalin intervention groups showed milder damage than that in aconitine poisoning group. Conclusions The neural toxic effect of aconitine in rats may be related to the imbalance between the neurotransmitter contents of excitatory Glu. Asp and inhibitory GABA,Gly in the cerebral cortex. Baicalin can decrease the contents of excitatory amino acid and elevate the inhibitory amino acid,therefore it may ameliorate the cerebral injury of acute aconitine intoxication in rats.