Effects of hesperetin on memory function and apoptosis-related protein expression in senile model rats
Objective To investigate the effect and mechanism of different doses of luteolin on memory function and apoptosis-related proteins of aging rats induced by D-galactose.Methods Forty-eight SPF-grade male Wistar rats aged 6-8 weeks were randomly divided into control group,model group,luteolin low-dose group(25 mg/kg),medium-dose group(50 mg/kg),high-dose group(100 mg/kg),and vitamin C group(100 mg/kg),with 8 rats in each group.D-galactose(1 000 mg/kg)was subcutaneously injected to establish the aging rat model,while luteolin was used for preventive treatment.The Morris water maze test was used to evaluate the learning and memory abilities of the rats.Transmission electron microscopy was used to detect the morphology of hippocampal neurons in rats.Spectrophotometry was used to detect the levels of interleukin-6(IL-6),interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),superoxide dismutase(SOD),malondialdehyde(MDA),and the total antioxidant capacity(T-AOC).RT-PCR was used to detect miR-34a mRNA expression.Western blot technique was used to detect the expression levels of silent regula-tor protein 1(SIRT1),B-cell lymphoma-2(Bcl-2),cleaved caspase-3,p53,and p21.Statistical analysis was performed using SPSS 22.0,and one-way ANOVA was used for multi-group comparison,followed by LSD-t test for further pairwise comparisons.Results(1)The differences in escape latency among the 6 groups of rats were statistically significant(F=120.93,P＜0.001).The latency of first finding the platform location of the model group rats((54.61±3.60)s)was higher than that of the control group((10.54± 4.27)s)(P＜0.05).The latency of first finding the platform location of rats in the low,medium and high dosage groups of luteolin((45.50±3.81)s,(37.46±2.94)s,(32.32±3.14)s)was lower than that of the model group((54.61±3.60)s)(all P＜0.05).(2)The differences of SOD,MDA,T-AOC,TNF-α,IL-1β,and IL-6 levels in the cerebral cortex of the 6 groups of rats were all statistically significant(F=281.636,75.119,208.228,38.999,28.428,52.767,all P＜0.001).Compared with the control group,the model group showed abnormal levels of inflammatory factors and antioxidant indexes.In the medium and high dos-age groups of luteolin,the SOD and T-AOC contents in the cerebral cortex of rats were higher than those in the model group(all P＜0.05),while the levels of MDA,TNF-α,IL-1β,and IL-6 were lower than those in the model group(all P＜0.05).(3)The differences in relative expression levels of miR-34a mRNA among the 6 groups of rats were statistically significant(F=81.439,P＜0.001).The expression levels of miR-34a mRNA in the hippocampal tissues of rats in the luteolin treatment group were lower than those in the model group(P＜0.05).(4)The differences in protein expression levels of SIRT1,p53,and p21 in the hippocam-pal tissues of the 6 groups of rats were statistically significant(F=159.946,38.342,123.608,all P＜0.001).The expression levels of p53 and p21 in the medium and high dosage groups of luteolin were lower than those in the model group(all P＜0.05),while the expression level of SIRT1 protein was higher than that in the model group(P＜0.05).(5)The differences in protein expression levels of Bcl-2 and cleaved caspase-3 in the hippocampal tissues of the 6 groups of rats were statistically significant(F=112.659,43.296,both P＜0.05).The expression levels of Bcl-2 in the low,medium,and high dosage groups of luteo-lin((0.24±0.04),(0.40±0.03),(0.48±0.05)pg/μg)were higher than those in the model group((0.09±0.06)μg)(P＜0.05),while the expression levels of cleaved caspase-3 in the low,medium,and high dosage groups of luteolin((0.62±0.04),(0.61±0.09),(0.51±0.10)μg)were lower than those in the model group((0.75±0.05)μg)(P＜0.05).Conclusions Luteolin can alleviate cellular oxidative damage through downregulating the miR-34a SIRT1/p53 signaling pathway and reducing cell apoptosis.
LuteolinSenilityMemoryHippocampusSilent mating type information reg-ulation 2 homolog-1p53Apoptosis
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