ABSTRACT
Increased oxidative stress arising from the maternal hyperglycemic-induced disturbances in fetal metabolism has been suggested to play a role in the pathogenesis of disturbed embryogenesis in diabetic pregnancies. Maternal diabetes in pregnancy and the associated hyperglycemia is also believed to expose the fetus to disturbed metabolic conditions in-utero creating a ‘metabolic memory’ that programs the fetus for glucose intolerance, diabetes mellitus and obesity later in life. Bitter kola (Garcinia kola) is a medicinal plant with a wide range of pharmacological effects including ant diabetic and antioxidant effects. In this study, the effects of aqueous extracts of Garcinia kola seed on the pregnancy outcome and early postnatal development of the offspring of pregnant alloxan diabetiPc and non-diabetic Wister rats was studied. Forty (40) nulliparous female Wister rats were used. Pregnancy was induced in all the rats, and diabetes induced in twenty (20) making two groups; pregnant diabetic and pregnant non-diabetic. These two groups were further subdivided into four groups of five rats each receiving different concentrations of the extract as follows; control, 100mg, 200mg, and 300mg/kg of body weight. The extract was administered orally as a single dose daily throughout gestation. The extract caused a reversal of the significant reduction of weight gain and significantly increased weight gain among the pregnant diabetic rats. It also significantly reduced the fasting blood glucose concentration in the hyperglycemic diabetic rats in a dose-dependent manner to values close to normal. These may be due to the insulinogenic effect of kolaviron an active principle of Bitter kola The extract significantly increased the litter size among the diabetic pregnant rats in a dose-dependent manner when compared with their control that showed a statistically significant reduction in litter size. This observed effect of the extract may be because of the anti-oxidative stress effects of kolaviron and ascorbic acid (constituents of Bitter kola) observed in previous studies. The extract also reduced the birth weight, excessive early post natal growth, and the high fasting blood glucose concentration on the weaning (21st) day, among the offspring of diabetic rat in a dose-dependent manner when compared with those of the diabetic pregnant control group. These may be due to the blood glucose lowering effect of the aqueous extract of Bitter kola seed among their mothers which leaves little or no excess glucose for the fetus to absorb and as such avert the major complications of diabetic pregnancy. The result of this study suggests that Bitter kola may have a protective effect against the adverse effects of diabetes in pregnancy on both the mother and the offspring.
TABLE OF CONTENTS
Certification page…………………………………………..
Dedication……………………………………………………
Acknowledgement ……………………………………………
Abstract….…………………………………………………..
Table of Contents…...……………………………………….
List of Tables ……...…………………………………………
List of Abbreviations………………………………………….
CHAPTER ONE: INTRODUCTION
1.1 Introduction ………………………………………………... 1
1.2 Justification for the study…………………………………... 2
1.3 Aims……………………………………………………….. .3
1.4 Objectives …………………………………………………..4
1.5 Operational definition of terms……………………………... 5
CHAPTER TWO: LITERATURE REVIEW
2.1 Diabetes mellitus in Pregnancy…………………………………………6
2.2 Alloxan Diabetes in Pregnancy ……………………………………….. 7
2.3 Pathophysiology of Diabetes in Pregnancy……………………………. 8
2.4 Fetal Complications in diabetes in pregnancy………………………… 11
2.4.1 Miscarriage……………………………………………………………11
2.4.2 Birth Defects and stillbirths……………….….……………………….12
2.4.3 Growth Restriction…….……………………………………………...13
2.4.4 Obesity…………………………………………..……………………13
2.4.5 Macrosomia…………………………………………………………...14
2.4.6 Metabolic Syndrome…………………………….……………………14
2.5 Management of Diabetes in Pregnancy…………………………………15
2.6 Traditional Phytotherapy…………………………………......................16
2.7 Traditional Phytotherapy in the Treatment of Diabetes………………...17
2.8 Garcina kola (Heckel)………………………………………..................18
2.8.1 Phytochemical Constituents of Bitter kola … 19
2.8.2 Bitter kola and Pregnancy and Lactation…………… 20
2.8.3 Some Previous Studies and Case Reports on Bitter kola... 20
CHAPTER THREE: MATERIALS AND METHODS
3.1 Plant Sample Collection and Extraction ………………..……….. 28
3.2 Experimental animals…………………………………………….. 28
3.3 Induction of pregnancy ………….……………………………… 29
3.4 Induction of diabetes....………………………………………….. 29
3.5 Acute Toxicity (LD50) Test…….…………………………………. 30
3.6 Animal Grouping and Treatment…………………………………… 30
3.7 Extract Administration…………………………………………….. 31
3.8 Selection of offsprings………………….…………….…………….. 32
3.9 Sample collection and Analysis……………………….…………… 32
CHAPTER FOUR: RESULT
4.1 The result of acute toxicity (LD50) test………………………… 33
4.2 The general physical observations on the non-diabetic and diabetic
pregnant rats used in the study and their offsprings. ……………. 33
4.3 The effect of Bitter kola extract on the weight of non-diabetic
and diabetic pregnant rats………………………………………… 35
4.4 The effect of Bitter kola extract on the fasting blood glucose of 10
non diabetic and diabetic pregnant rats…………………………… 37
4.5 The effect of Bitter kola extract on litter size of non-diabetic and
diabetic pregnant rats………………………..……………………… 39
4.6 The effect of Bitter kola extract on the weight of the offsprings of
non-diabetic and diabetic pregnant rats…………………………..….. 41
4.7 The effect of Bitter kola extract on fasting blood glucose level
of the offsprings of non-diabetic and diabetic pregnant rats on the
weaning (21st) day…………………………………………………… 43
4.7 The effect of Bitter kola extract on fasting blood glucose level
of the offsprings of non-diabetic and diabetic pregnant rats on the
weaning (21st) day…………………………………………………… 43
CHAPTER FIVE: DISCUSSION
5.1 The general observations during the study………………………. 46
5.1.1 The effect of Garcinia kola extract on the weight of non-diabetic
and diabetic pregnant rats……………………………………….. 46
5.1.2 The effect of Garcinia kola extract on the fasting blood glucose
of non-diabetic and diabetic pregnant rats………………………. 47
5.1.3 The effect of Garcinia kola extract on litter size of non-diabetic and
diabetic pregnant rats……………………………………………….. 48
5.1.4 The effect of Garcinia kola extract on the weight of the offsprings
of non-diabetic and diabetic pregnant rats………………………….. 49
5.1.6 The effect of Garcinia kola extract on fasting blood glucose
level of the offsprings of non-diabetic and diabetic pregnant rats
on the weaning (21st) day…………………………………………… 49
CHAPTER ONE
INTRODUCTION
1.1 INTRODUCTION
Compelling evidence suggests that exposure to an adverse fetal environment may enhance susceptibility to a number of chronic diseases in the future life of the offspring(Buzinaro et al, 2008; Simeoni and Barker, 2009).
Diabetes mellitus is a condition that occur during pregnancy that can substantially influence the development of the offspring in utero and postnatally. Diabetes mellitus is now a pandemic, affecting about 10million Nigerians (Ogbera et al, 2005) and about 350 million people worldwide (Ezzati et al, 2011) among who are pregnant women. It is well documented that the combined stress of diabetes mellitus and pregnancy creates a metabolic environment that is often life threatening to both the mother and the fetus (Freinkel, 1980; Metzger, 1991).
Hence, pregnancy among women that have pre-existing diabetes or gestational diabetes is associated with increased rate of adverse outcome for both mother and fetus (Kingsley, 2007; Shefali et al., 2006).
This is primarily due to altered maternal intrauterine environment, creating a situation in which the fetus is exposed to abnormal metabolic substrate (glucose) levels (Van Assche et al, 1991). There is an increased placental transfer of glucose from mother to fetus because of increased availability at the maternal site (Thomas et al, 1990). The compromised metabolic state of the fetus subsequently precipitates a variety of complications associated with ‘‘fuel-mediated teratogenesis’’ (e.g., hyperglycemia, hyperinsulinemia and macrosomia) (Freinkel, 1980; Metzger, 1991). One particularly devastating effect of diabetic pregnancy is that these conditions affect the fetus not only in utero, but also extend throughout the life of the offspring (Padilha et al, 2007; George et al, 2010). Additionally, maternal hyperglycemia stimulates abnormal fetal growth (Aberg et al, 2001) due to the greater availability of glucose in the blood flow (Maayan-Metzger et al, 2009), and this high weight fetus carries a high risk for 17 developing insulin resistance, glucose intolerance, obesity, and type 2 diabetes mellitus in childhood, adolescence and adulthood (Buzinaro et al, 2008; Simeoni and Barker, 2009)
The chances of reducing this poor outcome of pregnancy among diabetics are intricately related with the level of glycemic control (Shefali et al., 2006).
The fact that the economic cost of managing diabetes mellitus is high confers a very important role to medicinal plants in the management of diabetes mellitus especially in developing countries where resources are meager.
Consequently, a number of plants indigenous to Nigeria have been studied, and found to have hypoglycemic effects. These effects were traced to phytochemicals like alkanoids called active principles that can be extracted from plants(Ojewale, 2006; Osadebe et al., 2004). One of such anti-diabetic plants is Garcinia kola, commonly known as Bitter kola. It is an evergreen tree, indigenous to sub-Saharan Africa and belongs to a family of tropical plants called Guttifera (Ofusori et al., 2008). The seed is a masticatory, used for traditional hospitality in cultural and social ceremonies. Every part of the plant has shown to be of medicinal importance and has a wide range of medicinal effects, hence the name ‘wonder plant’ as it is commonly called.
Among the litany of its medicinal effects are; antidiabetic effects (Iwu et al, 1990), weight reducing effets (Koshy et al., 2001), leptin like action (Hayamizu et al., 2003), antihepatotoxic effects (Akintonwa and Essien, 1990), antioxidative stress and anti DNA 18 damage (Farombi, et al., 2004), detoxification of the toxic effects of other chemicals (Esimone et al., 2002; Nwokocha et al, 2011), etc.
1.2 JUSTIFICATION FOR THE STUDY
Diabetes mellitus is fast becoming the most common type of disease in school children (Pontiroli, 2004). This may be as a result of the reported more than doubling in therate of diabetes among expectant mothers between 2002 and 2008 (Lawrence et al., 2008).
The economic cost of managing diabetes is high. As a result, in the developing countries where resources are meager, there is a shift from contemporary to orthodox medicine since medicinal plants are relatively easier to find and less expensive alternative.
Coincidentally, some of the commonly consumed plant materials in Nigeria have been found to poses anti-diabetic properties. One of such anti-diabetic plantmaterials Bitter kola seed is used as a stimulant. It is also taken by pregnant women to stop nausea.
Although Bitter kola seed is a known anti-diabetic, there is paucity of data on;
(1) Its effects on pregnancies complicated by diabetes mellitus
(2) Early postnatal development of the offspring’s of such pregnancies.
Hence, the present study was therefore designed to investigate these.
1.3 AIM
The aim of this study is to determine the effect of consumption of Garcinia kola extract by diabetic pregnant rats on the pregnancy outcome and early postnatal development of their offspring.
1.4 OBJECTIVES
To determine the effect of consumption of Bitter kola extract by diabetic pregnant rats on;
i. The litter size.
ii. The early postnatal growth of the offsprings (from birth to weaning).
iii. The glucose profile of the offsprings at weanin
1.5 OPERATIONAL DEFINITION OF TERMS
Alloxan diabetes: A type of diabetes induced in rodens by the injection of alloxan hydrate. 20 Pregnancy weight gain: The weight gain during pregnancy.
Programming: The process whereby a stimulus or stress at a critical period of development of the rats results in a lasting or lifelong effect.
Teratogenic: Capable of causing developmental abnormalities in the fetus Diabetic pregnancy: Pregnancy complicated by diabetes mellitus irrespective of the type.
Early Postnatal development: This is the developmental processes that occur in the offsprings from the time of birth to the weaning day.
Gestation period: The period (in days) between the time when spermatozoa were first seen in vaginal smear and the time of delivery.
Glucose drain: The transfer of glucose from the maternal to fetal blood.
In-utero: Events occurring inside the uterus.
Litter Size: The number of offspring delivered by a pregnant rat.
Litter weight: The weight of the offsprings at birth (g).
Perinatal: Events that occur around the time of birth.
Pregestational (Pre-existing) diabetes: Diabetes existing before pregnancy, irrespective of the type.
Pregnancy weight gain: The weight gain during pregnancy.
Programming: The process whereby a stimulus or stress at a critical period of development of the rats results in a lasting or lifelong effect.
Teratogenic: Capable of causing developmental abnormalities in the fetus..
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