Protective effects of various doses of Glycyrrhizin on hippocampal tissue of young rats with status epilepticus / 中华实用儿科临床杂志

ABSTRACT

Objective:To study the protective effects of various doses of Glycyrrhizin on hippocampus of young rats with status epilepticus (SE).Methods:Lithium chloride and pilocarpine were injected intraperitoneally into male Sprague-Dawley (SD) rats (with a postnatal age of 18-21 days), so as to induce SE in rats.The rats were divided into 5 groups according to the random number table method: control group, SE group, SE+ low dose Glycyrrhizin group, SE+ medium dose Glycyrrhizin group and SE+ high dose Glycyrrhizin group.Three different doses of Glycyrrhizin (20 mg/kg, 40 mg/kg and 60 mg/kg) were injected intraperitoneally into the rats.The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in serum of SE rats were determined by enzyme linked immunosorbent assay.Quantitative real-time PCR (qRT-PCR) was used to detect the mRNA expression levels of TNF- α, IL-1β and IL-6 in hippocampus of SE rats.The expression levels of Bax, Bcl-2 and Caspase-3 in hippocampus were detected by Western blot.The damage of neurons was measured by hematoxylin and eosin (HE) staining and Nissl staining.Neurons apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The mitochondrial changes were observed under transmission electron microscopy.One-way ANOVA followed by Tukey post-hoc test was used for statistical analysis. Results:Compared to the control group, TNF-α[(369.69±58.07) ng/L vs. (75.46±14.64) ng/L], IL-1β[(242.27±25.23) ng/L vs. (45.29±5.90) ng/L] and IL-6[(288.15±24.60) ng/L vs. (46.59±8.80) ng/L] in the serum of SE rats were significantly up-regulated(all P<0.05). Compared to SE group, low, medium and high doses Glycyrrhizin could effectively reduce the levels of TNF-α[(216.67±8.31) ng/L, (158.81±5.03) ng/L and (113.69±12.54) ng/L vs. (369.69±58.07) ng/L], IL-1β[(131.21±5.50) ng/L, (86.60±7.79) ng/L and (65.06±4.39) ng/L vs. (242.27±25.23) ng/L] and IL-6[(150.24±9.48) ng/L, (101.70±5.85) ng/L and (91.60±2.81) ng/L vs. (288.15±24.60) ng/L] released in serum after SE occurred (all P<0.05). The neuronal damage, loss, apoptosis and mitochondrial damage were found in the hippocampus of SE rats.Glycyrrhizin could ameliorate these symptoms.Compared to the control group, Bax levels(0.57±0.01 vs. 0.14±0.01)and Caspase-3 levels(0.54±0.00 vs. 0.11±0.01)in the hippocampus of SE rats were markedly increased, while Bcl-2 levels(0.27±0.01 vs. 0.57±0.02)were decreased(all P<0.05). Compared to the SE group, low, medium and high doses Glycyrrhizin could effectively reduce the levels of Bax(0.51±0.02, 0.45±0.03 and 0.40±0.02 vs. 0.57±0.01)and Caspase-3(0.47±0.02, 0.42±0.02 and 0.37±0.01 vs. 0.54±0.00), and increase the levels of Bcl-2(0.41±0.02, 0.45±0.02 and 0.51±0.01 vs. 0.27±0.01)(all P<0.05). Conclusions:Glycyrrhizin can effectively protect the hippocampus of young rats with SE.