Therapeutic and Protective Potency of Bee Pollen Against Neurotoxic Effects Induced by Prenatal Exposure of Rats to Methyl Mercury.

Abstract

MeHg is a widely distributed environmental toxicant with harmful effects on the developing and adult nervous system. This study aimed to evaluate the therapeutic and protective efficacy of pollen grain in improving the toxic effects of MeHg, through the measurement of selected biochemical parameters linked to oxidative stress, energy metabolism, and neurotransmission in brain homogenates of male pups' neonates. Forty healthy pregnant female rats were randomly divided into five groups, and after delivery, each group was consisting of 10 male neonates: (1) neonates delivered by control mothers, (2) neonates delivered by bee pollen treated mothers who received bee pollen at the dose of 200-mg/kg body weight from postnatal day 0 for 4weeks, (3) neonates delivered by MeHg-treated mothers who received MeHg at the dose of 0.5mg/kg/day via drinking water from gestational day 7 till postnatal day 7 of delivery, (4) therapeutic group: neonates delivered by MeHg-treated mothers followed by bee pollen treatment who received bee pollen at the dose of 200-mg/kg body weight from postnatal day 0 for 4weeks, and (5) protective group: neonates delivered by MeHg and bee pollen-treated mothers. Mothers continued receiving the bee pollen at the same dose until day 21. Biochemical parameters linked to oxidative stress and energy metabolism and neurotransmission were investigated in brain homogenates of neonates from all the five groups. MeHg treatment showed an increase in oxidative stress markers like lipid peroxidation and catalase activity coupled with a non-significant decrease in glutathione level. Impaired energy metabolism was ascertained via the inhibition of creatine kinase and lactate dehydrogenase activities. Dramatic decrease of Mg2+ and K+ concentrations confirmed the neurotransmission defect. Interestingly, the bee pollen treatment was highly effective in restoring the catalase, lactate dehydrogenase, and creatine kinase activities in addition to normalizing the levels of Mg2+, K+, lipid peroxidation, and glutathione. Overall, the exposure to MeHg during the developing brain stages was highly effective to show signs and symptoms of neuronal toxicity. Furthermore, it has been concluded that bee pollen can be used safely to ameliorate oxidative stress, poor detoxification as well as metal ion defects, and neuronal death as a critical mechanisms involved in the etiology of numerous neurological disorders.