Unfavorable effect of levetiracetam on cultured hippocampal neurons after hyperthermic injury

Levetiracetam exposure during prenatal and postnatal period induces cognitive decline in rat offsprings, not completely prevented by Bacopa monnieri

OBJECTIVES

Levetiracetam (LEV) is an antiepileptic recommended during pregnancy. Bacopa monneri is a medicinal herb used in Ayurveda for improvement of cognition. Data on effects of LEV and Bacopa on cognition is inadequate. The study evaluated the cognitive effects of LEV on rat offspring of dams exposed to LEV and whether pretreatment with Bacopa monnieri, inhibits the potential cognitive decline by LEV.

METHODS

Pregnant rats were allocated into four groups of three rats each. Groups 1, 2, 3 and 4 received 2% gum acacia, LEV 270 mg/kg, LEV 270 mg/kg + Bacopa 100 mg/kg and LEV 270 mg/kg + Bacopa 200 mg/kg respectively during pregnancy and lactation. Three pups from all dams were chosen at random and exposed to passive avoidance, Hebb-Williams and Morris water maze tests to check for their cognition and relevant histopathology was done.

RESULTS

In the passive avoidance model groups 3 and 4, showed an increase in escape latency compared with group 2, demonstrating an improved learning (p=0.05). In Hebb-Williams maze, the time taken to reach reward chamber by group 2 increased compared to group 1, p=0.006, showing cognitive decline. Neuronal count in hippocampus and prefrontal cortex decreased significantly in group 2, which improved in group 3 & 4 however there was distortion of architecture in group 4.

CONCLUSIONS

LEV exposure in intrauterine and neonatal period induced cognitive decline in rat offsprings and Bacopa 100 mg/kg prevented LEV induced cognitive decline. However safety of exposure to Bacopa during the gestation period has to be evaluated.

Ultrastructural investigation of synaptic alterations in the rat hippocampus after irradiation and hyperthermia

This study aimed to investigate ultrastructural synaptic alterations in rat hippocampus after in utero exposure to irradiation (IR) and postnatal exposure to hyperthermia (HT). There were four groups in each of the time points (3^rd and 6^th months). IR group: Pregnant rats were exposed to radiation on the 17^th gestational day. HT group: Hyperthermia was applied to the rat pups on the 10th day after their birth. IR+HT group: Both IR and HT were applied at the same time periods. Control group: No IR or HT was applied. Rat pups were sacrificed after 3 and 6 months. Thin sections from the dentate gyrus (DG) and the CA3 of hippocampus were evaluated for synapse numbers by electron microscopy. Synapses were counted, and statistical analysis was performed. Abnormalities in myelin sheath, mossy terminals and neuropil were observed in the CA3 and DG of all groups. The synapses in the CA3 region were significantly increased in the IR-3^rd month, IR-6^th month, and IR+HT-3^rd month groups vs control group. Synapses were significantly increased in the DG of HT-3^rd month group. A trend for an increase in synapse numbers was seen in the CA3 and DG. Increased number of synapses in the rat hippocampus may be due to mossy fiber sprouting, possibly caused by in utero irradiation and/or postnatal hyperthermia.