Neuroprotective effects of Abelmoschus moschatus seed extract on fluoride-induced myelin degeneration in developing brain of rats

Abstract

Aim: Fluoride at higher concentrations affects various soft tissues, including brain, heart, kidney, and other tissues
in addition to dental and skeletal systems. Particularly, in brain it induces various complications such as oxidative
stress, alters in the levels of neurotransmitters, and histological changes. The aim of the present study is to report the
protective effects of Abelmoschus moschatus seed extract against sodium fluoride-induced neurohistological changes
with particular emphasis on myelin degeneration, cell shape, size, and Gamma-aminobutyric acid (GABA) as well as
aspartate alterations. In addition, antioxidants (glutathione peroxidase [GSH-Px] and superoxide dismutase [SOD]),
spatial navigation, and learning ability were observed. Materials and Methods: The pregnancy confirmed Wistar
rats were segregated into six groups, five subjects for each and doses started from 1st day of pregnancy. Control group
received normal tap water, fluoride group fed on 20 ppm fluoridated water, 3rd group treated with NaF (20 ppm)
+ A. moschatus aqueous extract (AMAE) (300 mg/kg b. wt.), 4th group received NaF (20 ppm) + A. moschatus
ethanolic extract (AMEE) (300 mg/kg b. wt.), and 5th and 6th groups treated with AMAE and AMEE alone. Treatment
continued for 51 days (21 gestational and 30 postnatal days [PND]).On PND 1, 7, 14, 21, and 30 rat pups were
sacrificed, dissected out the brain and used to assess antioxidants, GABA, aspartate and also used for histological
studies. Days 21 and 30, rats were used to behavioral studies before they sacrificed. Results and Discussion: The
decreased learning ability is observed in NaF exposed rats compared to control and protective groups of rats. GSH-Px
activity is increased and SOD activity is decreased in fluoride received rats. Moreover, GABA and aspartate levels
are increased (P < 0.001). The GABA, aspartate, and myelin have a crucial role in the maturation of brain. Decreased
neural connections, networks, dendritic branches, and degenerating myelin sheath are observed in NaF intoxicated
rats through H and E stain and luxol fast blue stain. These all are reverted on the administration of AMAE and AMEE
toward NaF toxicity. AMEE showed good results over AMAE. Conclusion: It is concluded that the seed extract of
A. moschatus possesses neuroprotective effects against fluoride toxicity.