Tualang Honey Reduced Neuroinflammation and Caspase-3 Activity in Rat Brain after Kainic Acid-Induced Status Epilepticus

Abstract

The protective effect of tualang honey (TH) on neuroinflammation and caspase-3 activity in rat cerebral cortex, cerebellum, and brainstem after kainic acid- (KA-) induced status epilepticus was investigated. Male Sprague-Dawley rats were pretreated orally with TH (1.0 g/kg body weight) five times at 12 h intervals. KA (15 mg/kg body weight) was injected subcutaneously 30 min after last oral treatment. Rats were sacrificed at 2 h, 24 h, and 48 h after KA administration. Neuroinflammation markers and caspase-3 activity were analyzed in different brain regions 2 h, 24 h, and 48 h after KA administration. Administration of KA induced epileptic seizures. KA caused significant (p < 0.05) increase in the level of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), glial fibrillary acidic protein (GFAP), allograft inflammatory factor 1 (AIF-1), and cyclooxygenase-2 (COX-2) and increase in the caspase-3 activity in the rat cerebral cortex, cerebellum, and brainstem at multiple time points. Pretreatment with TH significantly (p < 0.05) reduced the elevation of TNF-α, IL-1β, GFAP, AIF-1, and COX-2 level in those brain regions at multiple time points and attenuated the increased caspase-3 activity in the cerebral cortex. In conclusion, TH reduced neuroinflammation and caspase-3 activity after kainic acid- (KA-) induced status epilepticus.

Figure 1

TNF- α level in the cerebral cortex, cerebellum, brainstem, and serum of control and kainic acid-induced groups at multiple time points. Graph showed the levels of TNF-α in the cerebral cortex (a), cerebellum (b), brainstem (c), and serum (d) at 2 h, 24 h, and 48 h after KA administration in comparison to the relative control groups. In Figure 1(a), data are presented as median (IqR), n = 6 per group, for each time point. Statistical analysis: Kruskal-Wallis H test followed by Mann–Whitney U (MW) test with p<0.05 indicates significant difference. ^ap<0.05 compared to control group (MW), ^bp<0.05 compared to KA group (MW). In Figures 1(b), 1(c), and 1(d), data are presented as mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test followed by Tukey post hoc test with p<0.05 indicates significant difference. ^ap<0.05 compared to control group, ^bp<0.05 compared to KA group. ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; IqR; interquartile range; KA, kainic acid; TH, tualang honey; TNF-α, tumor necrosis factor alpha, TPM, topiramate; SEM, the standard error of the mean.

Figure 2

IL-10 level in the cerebral cortex, cerebellum, and brainstem of control and kainic acid-induced groups at multiple time points. Graph showed the levels of IL-10 in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration. Data are presented as Mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test with p<0.05 indicates significant difference. However, there was no significant difference (p>0.05) in the IL-10 level in all the brain regions or in the rat cerebral cortex, cerebellum, and brainstem among the experimental groups at 2h, 24 h, and 48 h after KA administration. Tukey post hoc test was not performed. ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; KA, kainic acid; TH, tualang honey; IL-10, interleukin-10; TPM, topiramate; SEM, the standard error of the mean.

Figure 3

IL-6 level in the cerebral cortex, cerebellum, and brainstem of control and kainic acid-induced groups at multiple time points. Graph showed the levels of IL-6 in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration. Data are presented as Mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test with p<0.05 indicates significant difference. However, there was no significant difference (p>0.05) in the IL-6 level in all brain regions or in the rat cerebral cortex, cerebellum, and brainstem among the experimental groups at 2h, 24 h, and 48 h after KA administration. Tukey post hoc test was not performed. ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; KA, kainic acid; TH, tualang honey; IL-6, interleukin-6; TPM, topiramate; SEM, the standard error of the mean.

Figure 4

AIF-1 level in the cerebral cortex, cerebellum, and brainstem of control and KA-induced groups at multiple time points. Graph showed the levels of AIF-1 in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration in comparison to the relative control groups. Data are presented as Mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test followed by Tukey post hoc test with p<0.05 indicates significant difference. ^ap<0.05 compared to control group, ^bp<0.05 compared to KA group. AIF-1, allograft inflammatory factor 1; ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; KA, kainic acid; TH, Tualang honey; TPM, topiramate; SEM, the standard error of the mean.

Figure 5

COX-2 level in the cerebral cortex, cerebellum, and brainstem of control and KA-induced groups at multiple time points. Graph showed the levels of COX-2 in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration in comparison to the relative control groups. In Figures 1(a) and 1(b), data are presented as mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test followed by Tukey post hoc test with p<0.05 indicates significant difference. ^ap<0.05 compared to control group, ^bp<0.05 compared to KA group. In Figure 1(c), data are presented as median (IqR), n = 6 per group for each time point. Statistical analysis: Kruskal-Wallis H test followed by Mann–Whitney U (MW) test with p<0.05 indicating significant difference. ^ap<0.05 compared to control group (MW), ^bp<0.05 compared to KA group (MW). ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; COX-2, cyclooxygenase-2; IqR, interquartile range; KA, kainic acid; TH, Tualang honey; TPM, topiramate; SEM, the standard error of the mean.

Figure 6

5-LOX level in the cerebral cortex, cerebellum, and brainstem of control and KA-induced groups at multiple time points. Graph showed the levels of 5-LOX in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration in comparison to the relative control groups. Data are presented as Mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test followed by Tukey post hoc test with p<0.05 indicating significant difference. ^ap<0.05 compared to control group, ^bp<0.05 compared to KA group. ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; KA, kainic acid; 5-LOX, 5-lipoxygenase; TH, tualang honey; TPM, topiramate; SEM, the standard error of the mean.

Figure 7

Caspase-3 activity in the cerebral cortex, cerebellum, and brainstem of control and KA-induced groups at multiple time points. Graph showed the activity of caspase-3 in the cerebral cortex (a), cerebellum (b), and brainstem (c) at 2 h, 24 h, and 48 h after KA administration in comparison to the relative control groups. Data are presented as Mean ± SEM, n = 6 per group for each time point. Statistical analysis: one-way ANOVA test followed by Tukey post hoc test with p<0.05 indicating significant difference. ^ap<0.05 compared to control group, ^bp<0.05 compared to KA group. ANOVA, one-way analysis of variance; BS, brainstem; CC, cerebral cortex; CB, cerebellum; KA, kainic acid; OD, optical density; TH, Tualang honey; TPM, topiramate; SEM, the standard error of the mean.