NEUROBEHAVIOURAL AND HISTOMORPHOLOGICAL EFFECTS OF HYOSCYAMINE FRACTION OF Datura stramonium SEEDS ON THE HIPPOCAMPUS AND DENTATE GYRUS OF DEVELOPING AND ADULT WISTAR RATS
NEUROBEHAVIOURAL AND HISTOMORPHOLOGICAL EFFECTS OF HYOSCYAMINE FRACTION OF Datura stramonium SEEDS ON THE HIPPOCAMPUS AND DENTATE GYRUS OF DEVELOPING AND ADULT WISTAR RATS
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Date
2021-03
Authors
ABDU, Idris Tela
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Abstract
Datura stramonium (D. stramonium) is one of the well-known traditional plants with
both poisonous and therapeutic properties due to the presence of tropane alkaloids.
Hyoscyamine is one of such alkaloids with suspected teratogenic tendencies,however,
received little attention in the literature.The study aimed to evaluate the effects of
hyoscyamine fractionofD. stramoniumseeds on the neurobehavioural and
histomorphology of developing hippocampus and dentate gyrus of Wistar rats. Two
thousand grams of fresh and mature D. stramoniumseeds wereprocured, extracted
andfractioned to detect the presence and quantify the amount of hyoscyamine using thinlayer
chromatography (TLC) and high-performance liquid chromatography (HPLC)
analyses respectively. Thirty-two (32) healthy Wistar rats comprised of adult males and
females (1:1), weighed 150-250 g were procured. The oestrus cycles of the female rats
were synchronized and the proestrus phases determined by vaginal cytology. Eight
(8)Wistar ratscomprised of malesand females(1:1) were randomly selected and mated
into four different groupsfor treatments at gestation, lactation, adolescence and adulthood
respectively.Each group was further divided equally into control and treatment
subgroups. A total of one hundred and twenty (120) litters were obtained after mating.
Thirty (30) litters fromgroup I received200 mg/kg in uteroof normal saline and the
hyoscyamine fraction of D. stramonium seeds ona gestational day (GD)15-20
respectively. Sixty (60)litters obtained from the group II and III were treated withnormal
saline, 400, 800 mg/kg hyoscyamine fraction on a postnatal day (PND)0-21 andPND22-
42respectively.Thirty (30) litters obtained in group IV were further subdivided into
fourgroups and treated withnormal saline, 200, 400 and 800 mg/kg bodyweight of the
fraction on PND56-77 respectively. Litters ingroup I was physically observed for gross
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congenital malformation of physical growth indices (eyes-opening, teeth eruption,
bilateral ear detachment and hair growth). Functional battery tests for motor reflex using
surface righting reflex (SRR), cliff avoidance (CAV) and negative geotaxis (NEG) was
conducted on the PND4, 5 and 6 respectively to assess the effects of the fraction on
motor reflexesinthe Wistar rat pups. Triple horizontal bar test (3HBT), Morris Water
Maze (MWM) and Novel Objects Recognition (NORT) tests were used to assess motor
coordination, spatial learning and memory and recognition ability inall groups when
theyreachedadulthood. The animals were sacrificed at end of every phase of the treatment
and in adulthood. The hippocampus was harvested for histology, stereology, Atomic
Absorption Spectrophotometry of selected trace/heavy elements (Cu, Ni and Zn), and
gene expressions studies. The data obtained were expressed as Mean±SEM using Minitab
17 statistical package. P<0.05 was considered statistically significant.
The results showed that 42 grams (2.10%) of crude ethanol extract of D.
stramoniumseeds were obtained from two thousand grams of the sample. Also,18 grams
(0.01%) hyoscyamine fraction obtained from the crude extract and yielded 24.09 μg/dl
hyoscyamine.No statistically significant difference (p> 0.05) in the physical growth
indices observed, however, a statistically significant difference (p< 0.05) SRR, CAV and
NEG were observed between the groups. There wasalso a statistically significant
decrease in bodyweight, NORT, Discrimination Index (DI), Novelty Preferences, in
Prenatal, Adolescence and Adulthood exposure and MWM test paradigms (p< 0.05). The
neuronal numbersin region CA1, CA3 and dentate gyrus (DG) ofthe hippocampus,
surface areas and volumes of the hippocampus in the treated groups significantly differed
(p<0.001) from the control groups. The expressions of the DLG3 and NeuroD1 genes
were also significantly downregulated (p<0.001) in the treated groups when compared to
the control. Significant differences in the amounts of the Cu, Ni and Zn (p<0.005) were
also observed in the treated groups during lactation, adolescence, and adulthood. A
variable degree of neurodegenerationand lesions such as pyknosis, cytoplasmic
vacuolation and nuclear hyperchromasia were observed in the treated groups.
In conclusion, ingestion of hyoscyamine fraction of D. stramoniumseeds at any stage of
development decreased the bodyweight, impaired motor reflexes, altered the trace
elements balance Cu, Ni and Zn balance, impaired recognitionability, spatial learning and
memory and downregulated the expressions of NeuroD1 and DLG3 in the hippocampus
of Wistar rats and neurodegenerations.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES, AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF THE DOCTOR OF PHILOSOPHY IN HUMAN ANATOMY
DEPARTMENT OF HUMAN ANATOMY,
FACULTY OF BASIC MEDICAL SCIENCES,
COLLEGE OF MEDICAL SCIENCES,
AHMADU BELLO UNIVERSITY,
ZARIA
Keywords
NEUROBEHAVIOURAL,, HISTOMORPHOLOGICAL EFFECTS,, HYOSCYAMINE FRACTION,, Datura stramonium SEEDS,, HIPPOCAMPUS,, DENTATE GYRUS,, DEVELOPING,, ADULT WISTAR RATS.