INVESTIGATION INTO THE EFFECT OF THE TOXICANTS ARSENIC AND MANGANESE ON MALE REPRODUCTIVE SYSTEM OF WISTAR RAT
CHAPTER ONE
INTRODUCTION AND LITERATURE REVIEW 1.1 INTRODUCTION.
In today’s industrialized world, exposure to pollutants in which heavy metals like arsenic, lead, manganese are an example is of high risk. These metals are present even in drinking water. Arsenic is mostly present in underground water. These metals are highly distributed in our environment and are thus consumed in quantities greater than what by the body requires (Ferrer, 2003).
Increased levels of arsenic in the environment, is an attribute to industrial product and waste, agricultural pesticides and herbicides. Although manganese is an essential element, toxicity can be gotten from drinking water, food, occupation and so on. Exposure to these heavy metals can cause poison and damage to models (the human body. Effects of arsenic have been reported in both human and experimental ATSDR a, 2012; Kannan et al., 2001). Mn exposure can also cause neurotoxicity (ATSDR b, 2007). Manganism, a consequence of exposure to high Mn levels, is a known neurological syndrome with many symptomatic analogies to Parkinson’s disease (Santamaria, 2008). Manganese and arsenic also target the same organ in the body, namely the brain (ATSDR, 2007a,b,c).
Given their co-existence in soil and atmosphere, exposure to toxicity does not occur in isolation (Kordaset al., 2010). Indeed, in the real world, exposures to complex mixtures are the rule, rather than exception (Scherer, 2005). Over the last several decades, the incidence of neurological diseases has increased (WHO, 2006).Mn poisoning results in an irreversible condition known as “manganism,’’ a neurodegenerative disorder that resembles Parkinson disease in both symptomatology and the underlying cellular mechanisms (Ellingsen et al., 2008; Martinez-Finley et al., 2012).
Neurological disorders induced by chronic metal exposure can be progressive and manifest clinically decades after the initial exposure (Gil and Pla, 2001). The onset of neurotoxic effects is largely subtle, insidiously manifested and unidentifiable as a clearly defined disease (Shy, 1993).
Exposure to arsenic- and lead-contaminated drinking water has been associated with an increased occurrence of congenital heart defects (CHDs). Groundwater is a vital hidden natural resource
(Tularam and Krishna 2009; Lashkaripour and Ghafoori 2011). Groundwater can be found in most environments and generally requires no prior treatment and can be found close to the points of demand often at low cost (MacDonald and Calow 2009). Arsenic poisoning or arsenicosis is a condition caused by the ingestion, absorption or inhalation of dangerous levels of arsenic, higher than the normal 10ppb which the body can tolerate.
The male reproductive system consists of two major parts: the testes, where sperm are produced, and the penis, according to Merck Manuals. The penis and urethra belong to both the urinary and reproductive systems in males. The testes are carried in an external pouch known as the scrotum, where they normally remain slightly cooler than body temperature to facilitate sperm production.Metals may cause a wide spectrum of reproductive and developmental adverse effects such as reduced fertility, abortions, retarded growth at the intrauterine cavity, skeletal deformities, malformations and retarded development especially of the nervous system.
Arsenic and manganese tend to decrease motility of sperm in the male reproductive system even though the sperm are active.
The important mechanisms of action of arsenic are placental transfer, oxidative stress, direct binding with thiol group etc.
The toxicity of arsenic in male and female reproductive organs is also explained. It also throws some light on the therapeutic strategies for metal toxicity.Manganese is a suspected reproductive toxicant and exposure to it has the potential to negatively affect the human reproductive system. The severity and nature of the adverse effect is variable and can be influenced by factors such as level of exposure and individual sensitivity to the chemical. Effects on the male reproductive system can include such things as altered sexual behavior, altered fertility and problems with sperm shape or count.
Manganese also have some positive effects on the reproductive system, they include It helps to produce sex hormones and sperm. Manganese acts as a catalyst for breaking down fatty acids and cholesterol. Manganese has a positive effect on the male reproductive system,It also enhances the brain’s aptitude for receiving and sending messages,Sex hormones are produced in the pituitary gland, where a considerable amount of manganese exists. Because of this, manganese is believed to assist in sexual health.
Studies have been carried out on the individual effect of manganese and arsenic on the male reproductive system, this research however concentrates on both their individual effect and also their combined effect on the reproductive system. Earlier studies have shown that both accumulate in the brain and affect production of hormones.
