ABSTRACT
This study examines the effects of low dose x-rays on the pH, sperm count, and sperm motility of the epididymal sperm cells of wistar rats. An experimental survey (case control study design) was adopted and a purposive sampling technique was used to select the species of mammals used for the experiment while a convenient sampling technique was used to select a nearby animal farm and a simple random technique was used to select the population of the male rats used. The population were divided into three test groups and a control group with test groups exposed to x-rays using a stationary x-ray machine and their epididymis extracted with a dissecting set and pH, sperm count and motility checked using a pH meter ( for pH) and the others performed with a microscope. Anova test was used to perform and analyze the data collected.
Findings here showed that at low dose of x-ray:
The pH of the epididyma sperm cell were not affected
The sperm count and motility of the spermatogonia and spermatocytes were affected while the spermatozoa ( matured cells) were spared.
This study recommends that there is need for great adhesion to the use of gonad shield in practice to avoid exposing male patients to adverse effect of radiation.
TABLE OF CONTENT
Title page .....................................................................................................i
Dedication…………………………………………………………………ii
Approval page…………………………………………………………….iii
Certification……………………………………………………………….iv
Acknowledgement…………………………………………………………v
Table of contents…………………………………………………………..vi
List of tables……………………………………………………………….vii
List of figures………………………………………………………………viii
Abstract…………………………………………………………………….ix
CHAPTER ONE: INTRODUCTION
1.1: Background of study………………………………………………….1
1.1.1 Medical procedures .............................................................................2
1.1.2 Mode of generation of x-ray.................................................................3
1.1.3 Area of utilization ................................................................................4
1.1.4 Epididymis ...........................................................................................5
1.1.5 Sperm cell .............................................................................................5
1.1.6 Biological Effects of ionizing radiation ...............................................6
1.2: Statement of Problem…………………………………………………7
1.3: Specific Objective of study……………………………………………8
1.4: Significance of study………………………………………………….8
1.5: Scope of study…………………………………………………………9
1.6: Definition of terms………………………………………..9
1.7: Literature review……………………….............................................14
CHAPTER TWO: THEORETICAL BACKGROUND
2.1: Radiation ……………………………………….............................. 16
2.2: Sources and uses of ionizing radiation…………………………………23………..
2.2.1: Radiation Dose …………………………………………………………24
2.3 Reproductive Anatomy Of Rats …………………………………………26…..
2.3.1 Reproduction Organ …………………………………………26
2.4 Production of sperm cells ( spermatozoa) …………………………35
2.4 .1 Factors Influencing sperm cell production……………………...........36
2.5 Evaluation of sperm cell ………………………………………….38
CHAPTER THREE: RESEARCH METHODOLOGY
3.1: Experimental Animals……………………………………...........40
3.2: Research Design…………………………………………………40
3.3: Sampling Technique…………………………….........................41
3.3.1: Selection Criteria……………………………………………...41
3.3.2: Sampling Size…………………………………………………42
3.4: Instrumentation/ Materials………………………………………42
3.5: Conduct of Study……………………………………………......43
3.6: Method of Data Analysis………………………………………46
CHAPTER FOUR: RESULTS
4.1: Data presentation…………………………………………………….47
CHAPTER FIVE: DISCUSSION AND IMPLICATIONS OF RESULTS, CONCLUSION AND RECOMMENDATIONS
5.1: Discussion ...............................................……………………………….64
5.1.1: Objective I ( the effects of low dose x-ray on pH of epididyma sperm cell)...........................64
5.1.2: Objective II (the effects of low dose x-ray on sperm count of epididyma sperm cell)..65
5.1.3: Objective 2 (the effects of low dose x-ray on sperm motility of epididyma sperm cell)…………………............ 66
5.1.3: Objective 3 (the effects of low dose x-ray on sperm motility of epididyma sperm cell)………………………………..
5.2: summary and conclusion ..................................................................................67
5.3: recommendations ..............................................................................................68
5.4: areas for further study........................................................................................68
5.5: Limitation of study .............................................................................................69
References...................................................................................................................70
Appendix ................................................................................................................... 73
LIST OF TABLES
Table 1: One-way Anova test of pH for the control and test group................................... 47
Table 2: One-way Anova test of sperm count for the control and test group......................49
Table 3: One-way Anova test of sperm motility for the control and test group................. 52
Table 4: the distribution of the mean± S.E.M of the parameters in the various groups following their days after exposure..56
Table 5: one-way ANOVA test of pH for the different days after exposure to x-ray....... 58
Table 6: one-way ANOVA test of sperm count for the different days after exposure to x-ray.....59
Table 7: one-way ANOVA test of sperm motility for the different days after exposure to x-ray................................ 60
Table 8: the distribution of the mean± S.E.M of the parameters in the various days after exposure following the different groups 62
LIST OF FIGURES
Fig 1: the reproductive system of male rats ...................................... 30
Fig 2: heads of released sperm from three species .............................. 34
Fig 3: Stages in the formation of sperm cells ........................................ 35
Fig 4: clustered out sperm cells when viewed under the microscope ........46
Fig 5: Spaced out sperm cells when viewed under the microscope ............ 46
Fig 6: line graph shows the pH variation in the different groups after different time of exposure ..........48
Fig 7: line graph shows the sperm count variation in the different groups after different time of exposure ...........................................51
Fig 8: line graph shows the motility variation in the different groups after different time of exposure ....................................54
INTRODUCTION
There are many sources of harmful radiation. Industrial radiographers are mainly concerned with exposure from x-ray generators and radioactive isotopes, but let's start by considering sources of radiation in general. It is important to understand that eighty percent of human exposure comes from natural sources such as outer space, rocks and soil, radon gas, and the human body. The remaining twenty percent comes from man-made radiation sources, such as those used in medical and dental diagnostic procedures1.
One source of natural radiation is cosmic radiation. The earth and all living things on it are constantly being bombarded by radiation from space. The sun and stars emits EM radiation of all wavelengths1. Charged particles from the sun and stars interact with the earth’s atmosphere and magnetic field to produce a shower of radiation, typically beta and gamma radiation. The dose from cosmic radiation varies in different parts of the world due to differences in elevation and the effects of the earth’s magnetic field.
There are also a number of manmade radiation sources that present some exposure to the public. Some of these sources include tobacco, television sets, smoke detectors, combustible fuels, certain building materials, nuclear fuel for energy production, nuclear weapons, medical and dental X-rays, nuclear medicine, X-ray security systems and industrial radiography. By far, the most significant source of man-made radiation exposure to the average person is from medical procedures, such as diagnostic X-rays, nuclear medicine, and radiation therapy1.
1.1.1MEDICAL PROCEDURES
Medical diagnostic procedures used to define and diagnose medical conditions are currently the greatest man-made source of ionizing radiation exposure to the general population. However, even these sources are generally quite limited compared to the general background radiation on Earth.
The risks and benefits of radiation exposure due to medical imaging and other sources must be clearly defined for clinicians and their patients. This work is a general overview for the population, who should understand the fundamentals of medical ionizing radiation and the general associated risks especially on epididyma sperm cell. This work will also acquaint the practitioner with relative doses of common radiographic procedures as well as natural background radiation.
The use of ionizing radiation in medicine began with the discovery of x-rays by Roentgen in 1895. Ionizing radiation is the portion of the electromagnetic spectrum with sufficient energy to pass through matter and physically dislodge orbital electrons to form ions. These ions, in turn, can produce biological changes when introduced into tissue2.
Ionizing radiation can exist in 2 forms:
i. As an electromagnetic wave;
This include x-ray or gamma ray.
ii. As a particle;
This may be in the form of an alpha or beta particle, neutron, or proton.
1.1.2MODE OF GENERATION OF X-RAY
X-rays are machine-generated, it is produced when rapidly moving electrons that have been accelerated through a potential difference of the order of 10-3 to 10-6 volts are allowed to strike a metal target. The kinetic energy of the electrons is converted in 3 principal way.
1. Less than 1% is converted to x-radiation
2. Approximately 99% is converted into heat by increasing the thermal vibration of the atom of the target which may rise considerably.
Meanwhile gamma rays are electromagnetic waves that are emitted from the nucleus of an unstable atom. Different forms of ionizing radiation have differing abilities to generate biologic damage
For the purpose of this study, I will lay more emphasis on x-rays which is used in the diagnostic imaging field.
x-rays can further be divided into either;
i) Hard radiation
ii) Soft radiation
Based on the dosage given, it can either;
Low dose;
This are doses that ranges from 1rad to 20rads. This is normally encountered in diagnostic field. Though low, they tend to have effects on many sensitive organs of the body and these doses can be received in various different ways. This work is out to investigate the effect these low dose x-radiation (which are received in diagnostic radiation) on the various semen parameters
High dose; which is normally encountered in therapeutic cases
These dosage are measured in sievert and its effects is dependent on the specie being studied.
1.1.3AREA OF UTILISATION;
As seen above, low dose radiation are encountered in diagnostic radiography in the medical field. Diagnostic radiography includes areas where diseases and illnesses are diagnosed using ionizing radiation. This comprises if doses received during conventional radiography such x-ray of the extremities, skull, abdomen, pelvis etc. and that in fluoroscopy during special examination like cystography, micturating urethro- cystography (MUCG) etc. It is also encountered in computed tomography examinations where images are gotten in slices of the patient body to diagnose diseases that cannot be easily seen on conventional radiography. This could include CT pelvis, skull, abdomen etc.
1.1.4EPIDIDYMIS:
The seminiferous tubules join together to become the epididymis. The epididymis is a tube that is about 2 inches that is coiled on the posterior surface of each testis. Within the epididymis the sperm complete their maturation and their flagella become functional. This is also a site to store sperm until the next ejaculation. Smooth muscle in the wall of the epididymis propels the sperm into the ductus deferens.. Vasa efferentia from the rete testis open into the epididymis which is a highly coiled tubule5. The epididymis has three parts-
1) Head or caput epididymis- it is the proximal part of the epididymis. It caries the sperms from the testis.
2) Body or corpus epididymis- it the highly convoluted middle part of the epididymis
3) Tail or cauda epididymis- it is the last part that takes part in carrying the sperms to the vas deferens. Epididymis keeps sperms for sometimes, gives nourishment to it. The cauda epididymis continues to form less convoluted vas deferens3.
1.1.5SPERM CELL:
Sperm cells originates solely from the testicles, and this is where sperm develop. The initial spermatozoon process takes around 70 days to complete. The spermatid stage is where the sperm develops the familiar tail. The next stage where it becomes fully mature takes around 56 days when its called a spermatozoan4. Subsequently, the semen wherein the sperm is carried is produced in the seminal vesicles, prostate gland and urethral glands.
sperm quantity and quality are the main parameters in semen quality, which is a measure of the ability of semen to accomplish fertilization. Thus, in rats, it is a measure of fertility in a male rat. The genetic quality of sperm, as well as its volume and motility, all typically decrease with age4.
Sperm were first observed in 1677 by Antonie van Leeuwenhoek8 using a microscope, he described them as being animalcules (little animals), probably due to his belief in preformationism, which thought that each sperm contained a fully formed but small human4.
1.1.6Biological Effects of Ionizing Radiation
Radiation damages the cell by damaging DNA molecules directly through ionizing effects on DNA molecules or indirectly through free radical formation. A lower dose delivered through a long period of time theoretically allows the body the opportunity to repair itself. Radiation damage may not cause any outward signs of injury in the short term; effects may appear much later in life5
Deterministic effects, such as cell killing, can be more immediate and have a threshold above which severity increases with radiation dose. However, the threshold is not necessarily the same in each individual or tissue. While healing may ensue, necrosis and fibrotic changes in internal organs, acute radiation sickness, cataracts, and sterility may also occur. For acute deterministic effects, large doses are usually required, such as 1-2 Gy or 1-2 Sv.
Stochastic effects, such as mutations, can result in cancer and hereditary effects. Cancer induction can have a long latency period. Estimating cancer risks associated with diagnostic x-rays using epidemiological tools is difficult because of extrapolation to low radiation doses, recall bias, and different x-ray energies used at various kiinstitutions. Most low-dose human ionizing radiation risk estimates come from the atomic bomb survivors in Japan. Other sources of information include laboratory cellular mutation studies and studies on various strains of mice; of course, the applicability to humans remains to be seen.
Finally other main consequences of radiation are hereditary effects. Radiation damage to the gonads during the reproductive period of life produces mutations to the gametes. Inherited diseases can encompass a range of mild disorders to serious consequences, including death or severe mental defects. However, no human population studies have shown hereditary effects from typical background ionizing radiation doses. Furthermore, some studies of the offspring of atomic bomb survivors have not shown statistically significant increases in hereditary defects or cancers5.
