The effects of pre-treatment with olibanum and its constituent, boswellic acid on synaptic plasticity impairments induced by lipopolysaccharide in rats.

Abstract

Olibanum (OLIB) and its component boswellic acid (BOSA) are suggested to have anti-inflammatory, anti-oxidant and neuroprotective effects. In the present work, we examined effect of OLIB, and BOSA on the synaptic plasticity impairment and oxidative stress indicators in a rat model of neuro-inflammation induced by lipopolysaccharide (LPS). Forty rats were divided into the following four groups: (1) Control, (2) LPS, (3) OLIB (200 mg/kg), and (4) BOSA (10 mg/kg). The animals were pre-treated with OLIB extract, BOSA or the vehicle 30 min before LPS (1 mg/kg) administration, for 6 days. On the 6th day, electrophysiological recording was done. Long-term potentiation (LTP) from CA1 area of hippocampus was assessed. The animals were then sacrificed and their brains were removed for evaluation of the levels of interleukin-6 (IL-6), nitric oxide (NO) metabolites, malondialdehyde (MDA), thiol, superoxide dismutase (SOD) and catalase (CAT) in the cortex. Administration of LPS decreased amplitude (p<0.001) and slope (p<0.01) of field excitatory postsynaptic potential (fEPSP). Pre-treatment enhanced these parameters (p<0.05 to p<0.001). LPS also increased cortical levels of IL-6 (P<0.01), NO, and MDA (p<0.001) while decreased thiol, SOD (p<0.001), and CAT (p<0.05). OLIB and BOSA diminished IL-6 (p<0.05-p<0.001), NO (p<0.01-p<0.001) and MDA level (p<0.01 and p<0.001, respectively) while improved SOD (p<0.05 and p<0.001, respectively), CAT (p<0.05 and p<0.001, respectively) and thiol content (p<0.001). The results showed that OLIB and BOSA could improve synaptic plasticity impairment induced by LPS as shown by a decrease in an inflammation indicator along with the anti-oxidant effects.