Khat (Catha Edulis) Extract Use and Its Effects Following Withdrawal on Endocrine and Gonadal Function in Male Rabbits
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Date
2019
Authors
Maluki, Esther Muthio
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Gonadal and endocrine effects following withdrawal from sub-chronic to chronic khat (Catha
edulis) use remains scanty. Most literature available, though contradictory, highlights on
effects of khat on functional systems of the body including the reproductive system in
humans and experimental animals during khat exposure. This information, to a large extent,
does not provide insights into the possible recovery of „khat addicts‟ from the vice. The aim
of this study was to investigate effects of khat extract during sub-chronic exposure and
accompanying effects on reproductive function in male rabbits following withdrawal from
use. Fresh leaves and shoots of khat were weighed, crushed with mortar and pestle, and
dissolved in distilled water in a conical flask for extraction. The working volume of the stock
solution for each dose was obtained by factoring in the body weight of the rabbits. The final
volumes were standardised by adding normal saline. Sixteen male rabbits were grouped into
four groups of 4 rabbits each. The first group (G1) were controls and administered normal
saline while the other three groups (G2, G3 and G4) were administered 1.0 g/kg, 10 g/kg and
20 g/kg body weight of khat extract respectively. The test animals were administered the
doses of khat extract via oral gavage on alternate days of the week (Monday, Wednesday and
Friday) for 12 weeks. Thereafter two animals from each group were sacrificed for
histological evaluation of testis, epididymis and kidney. The remaining 2 animals from each
group were taken through the withdrawal period of 4 weeks before sacrifice. Blood samples
were collected, processed and plasma stored at -20oC until assayed for FSH and testosterone
levels for treatment groups as well as controls. Hormonal data and data on clinical
observation for difference in means among groups and over the experimental period were
analysed by two- way ANOVA at 95% confidence interval followed by Tukey‟
s multiple
comparison for post hoc test. Intergroup analysis was done using paired t test. The
relationship between weight and levels of testosterone was done using spearman rank
correlation analysis at 5% significance level. Khat extract at low dose increased plasma levels
of testosterone and FSH while at high dose and over experimental time significantly
suppressed testosterone production but the FSH levels were only slightly reduced. This was
reversed during withdrawal period where plasma testosterone and FSH in both controls and
treatment groups showed no significant difference in their measurements. Histological data
on testis during sub-chronic exposure showed vacuolation in germinal epithelium of
moderate and high dose treatment groups over experimental period. The same was observed
in the epithelial lining of proximal convoluted tubules of kidney nephrons of high dose
treatment groups at sub-chronic exposure. However, histological sections of the epididymis
appeared unaffected at all doses of khat extract. Following withdrawal from sub-chronic
exposure, testicular, epididymal and kidney histology of all treatment groups appeared to
regenerate from cellular damage when compared to controls. These results in rabbits have
demonstrated for the first time that structural alterations on reproductive system reported
variously in literature on khat addicts are reversible following withdrawal from heavy and
long-term use in man.
Description
A Thesis Submitted in Partial Fulfilment of the Requirements for the Award of the Degree of Master of Science (Animal Physiology) In the School of Pure and Applied Sciences of Kenyatta University, October 2019
Keywords
Khat, Endocrine and Gonadal Function, Male Rabbits