Evaluation of the Effects of Aqueous Allium Sativum (Garlic) Extracts on Lead-induced Changes on the Hippocampus and Cerebellum of Wistar Rats
Chapter one
Aim and Objectives of the study
Aim of the study
This study is aimed at determining the effects of aqueous garlic extract on lead induced damages on the hippocampus and cerebellum of adult Wistar rats.
Objectives
This study seeks to:
- Evaluate the neurobehavioral effects of aqueous Allium sativumextract on lead induced changes on the hippocampus and cerebellum of adult Wistar rats using Morris water maze and beam walking methods
- Biochemically evaluate the effect of aqueous allium sativum extract on lead induced changes on hippocampus and cerebellum of adult Wistar rats using oxidative stress markers namely; catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and lipid peroxidation (LPO).
- Evaluate the possible histological and histochemical effects of aqueous Allium sativum extract on lead induced changes on the hippocampus and cerebellum of adult Wistar rats using routine Hand E staining and cresylviolet
CHAPTER TWO
LITERATURE REVIEW
Background
Metals are elements found in nature usually in the form of their respective compounds which are widely used in industries, affecting human health through occupational and environmental exposure. Most notably, are the heavy metals which have specific density greater than 5 g/cm3such as mercury (Hg), cadmium (Cd), arsenic (As) and lead (Pb). Most of these heavy metals persist in the environment and produce a variety of adverse effects because they are generally not biodegradable (Alissa and Ferns, 2011). One of the leading metallic xenobiotic is lead (Pb) and because of the unique properties of lead, like softness, high malleability, ductility, low melting point and resistance to corrosion, have resulted in its widespread usage in different industries like automobiles, paint, ceramics, plastics, etc. This in turn has led to a manifold rise in the occurrence of free lead in biological systems and the inert environment (Flora et al., 2012).
Lead poisoning also known as plumbism, colicapictorum, saturnism, devon colic, or painter’s colic is a type of metal and a medical condition in humans and other vertebrates caused by increased levels of the heavy metal lead in the body (Karri et al., 2008). Signs and symptoms may be different in adults and children. Early symptoms of lead poisoning in adults are commonly nonspecific and include depression, loss of appetite, intermittent abdominal pain, nausea, diarrhea, constipation, and muscle pain (Karri et al., 2008). Other early signs in adults include malaise fatigue, decreased libido and problems with sleep. An unusual taste in the mouth and personality changes are also early signs (Patrick, 2006). Children are more at risk of lead poisoning because their smaller bodies are in a continuous state of growth and development (Landrigan, 2002). Lead is absorbed at a faster rate compared to adults, which causes more physical harm than to older people. The classic signs and symptoms in children are loss of appetite, abdominal pain, vomiting, weight loss, constipation, anemia, kidney failure, irritability, lethargy, learning disabilities, behavioral problems, and slow development of normal childhood behaviors, such as talking and use of words, and permanent intellectual disabilities are both commonly seen (Landrigan 2002). Lead poisoning has also been reported to cause oxidative damage to DNA by interfering with the incision step of DNA repair system, thus inducing carcinogenicity (Koedrith and Young, 2011). Also, a couple of proteins in vivo and the plasma membrane have lost their integrity and function as a result of plumbism (Abamet al., 2008).
CHAPTER THREE
Materials and Methods
Experiment rats
Forty five(45) Wistar rats (both sexes) were used in this study and were purchased from the Animal House Centre, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria Nigeria. The ratswere maintained at the Animal House, Department of Human Anatomy, Faculty of Medicine, Ahmadu Bello University, Zaria Nigeria, under controlled conditions.
CHAPTER FOUR
RESULTS
Effect of aqueous Garlic extract on lead induced changes on Body Weight of the Rats
The results on the effect of lead administration on body weight changes are shown in Table 4.1. The results showed a significant difference in weight between the Control and the treated Groups at (P˂ 0.05). There was a gradual increase in the mean body weight of the rats in the Control group (Group one) as shown in Table 4.1. However, there was a gradual decrease in body weight of the rats in the lead treated groups namely Groups 2, 3,4, and 5 as compared with the rats in the Control group.
In Groups 2 and 3, there was a gradual decrease in the final body weight and when compared with the rats in the Control group was statistically significant (P˂ 0.01), after three weeks of lead administration. On the other hand, the rats in the lead and aqueous garlic extract or Succimer treated groups, there were gradual increases in the body weight which when compared with the rats in the Control group(Group one) were not significant after second and third weeks of administration but was statistically significant after the first week of administration(P˂ 0.05)
CHAPTER FIVE
DISCUSSION
Effect of aqueous Garlic extract on lead induced changes on Body Weight
It has been reported that rats that are continuously exposed to heavy metals such as mercury (Hg), cadmium (Cd), arsenic (As) and lead (Pb) usually results in reduction in the body weight(Nwokochaet al., 2011). The present study was carried out to study the effect of lead induced changes on the hippocampus and cerebellum of adult Wistar rats. Our study showed that there were reduction in mean body weight of the rats in the lead treated groups only when compared with the rats in the Control group.
This reduction in the mean body weight with continuous exposure to lead might be explained on the basis of anorexia which is induced by lead exposure (Klaassen, 2001). Another possible explanation for the reduction of the mean body weight may be the decreased muscle mass and cachexia due to the oxidative stress induced by lead. This is because there was evidence that heavy metal toxicity was associated with oxidative stress (Yehet al., 2009) which according to many researchers was associated with muscle wasting and cachexia leading to low body weight (Buck et al., 1998).
CHAPTER SIX
CONCLUSION AND RECOMMENDATIONS
CONCLUSION
It can be concluded from the present study that;
Lead acetate has induced changes in the body weight of the adult Wistar rats.
Rats exposed to lead acetate (Pb2+) showed impairment in spatial learning and memory in Morris water maze and Beam walking tasks, but rats that are exposed to the same concentration of lead (Pb2+) and aqueous garlic extract did not show impairment in Morris water maze and Beam walking tasks performance as shown by the reduction in the time taken to perform the tasks.
Aqueous garlic extract has positive effect on the lead induced changes on GSH, CAT, SOD activities and MDA levels. The study showed that MDA levels were increased and enzyme (GSH, CAT, and SOD) activities were decreased in lead treated rats compared to the control group while there was preserved effect of lead acetate in the rats treated with lead acetate and aqueous garlic extract or Succimer(DMSA).
RECOMMENDATIONS
- Further studies are recommended to investigate the molecular and cellular mechanisms responsible for increases in antioxidant enzyme activity (CAT, SOD, and GSH) and decreases MDA
- It is recommended that further work should be carried out in order to quantify the amount of lead that could possibly be deposited in the hippocampus and cerebellum.
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