DETERMINATION OF PRION PROTEIN (PRP) AND CHANGES IN FERTILITY HORMONES WITH SLEEP DEPRIVATION IN ALBINO RATS

DETERMINATION OF PRION PROTEIN (PrP) AND CHANGES IN FERTILITY HORMONES WITH SLEEP DEPRIVATION IN ALBINO RATS

ABSTRACT

Wistar albino rats, numbering thirty five (35), were nurtured in the animal house of University of Nigeria Enugu Campus and used for this work. This work is designed to determine the presence of prion (PrP) in Wistar albino rats and the possible changes that sleep deprivation can cause in PrP and fertility hormones. Twenty four (24) of the animals (15 females 9 males) were successfully sleep-deprived for 14 days while 11 were not deprived of sleep. The non-sleep deprived rats were used as a control group in addition to PrPc commercial control, for the prion protein determination. The body weights of the rats were obtained before and after sleep deprivation. Serum samples were collected before and after sleep deprivation for the fertility hormone assay while brain tissues were extracted from each sleep deprived and non-sleep deprived rat after 14 days for prion protein determination and histological studies. Single platform sleep deprivation technique was used for sleep deprivation, ocular venipuncture for blood collection, euthanization for sacrificing the rats and enzyme linked immunosorbent assay method for both hormone assay and prion protein determination respectively. Part of the brain tissues were prepared histologically (sectioning and staining) using congo-red staining technique for possible sleep deprivation induced morphological changes. The presence of PrP as determined, was confirmed by comparison of the values of the two control groups and test samples while a significant increase (p < 0.05) in PrP concentration after sleep deprivation was observed when compared with non sleep deprived group of albino rats. Sex hormones such as testosterone and oestradiol, decreased significantly (p < 0.05). The concentrations of prolactin and thyroid stimulating hormone and the body weight of the rats also showed a significant decrease (p < 0.05) after sleep deprivation compared with the normal control rats. The concentrations of follicle stimulating hormone and luteinizing hormone had no significant (p > 0.05) changes after sleep deprivation when compared with control group of albino rats. There was decrease in oestradiol, testosterone, prolactin, thyroid stimulating hormones and body weight of rats while FSH, LH and brain tissues showed no significant changes. There were also no observable changes in the brain tissue morphology after sleep deprivation. In conclusion, there was PrPCinduction following sleep deprivation in albino rats. It is therefore recommended that sleep deprivation should be put into consideration in infertility cases and more work should be done on Prion proteins for neuropathological cases.

CHAPTER ONE

INTRODUCTION

Sleep is the natural state of bodily rest observed in mammals, birds, many reptiles, amphibians and fishes. It is equally a state of unconsciousness from which a person or animals can be aroused. In this state the brain is relatively more responsive to internal than external stimuli. In contrast, coma is also a state of unconsciousness from which a person or animals cannot be aroused (Max, 2006). Sleep is homeostatic; therefore it is controlled by the body’s internal balance (Max 2006). It is considered critical for maintenance of health, support of life, restoration of body and brain functions and promotion of neural-immune interaction (Aurell and Elqvist, 1985; Everson et al., 1989). These are reflected in the roles of sleep in the brain for memory co-ordination and teaching (Turner et al., 2007). Through its role in hormone activities such as in growth hormone, thyroid stimulating hormone and prolactin to mention a few, metabolic processes are properly co-coordinated and carbohydrate storages are carried out (Bonnet and Arand, 2003; Everson and Read, 1995).

Sleep deprivation, a general lack of necessary amount of sleep, which may occur as a result of sleep disorder or deliberate inducement or torture, is deleterious to health when it is prolonged. It has been scientifically observed that prolonged sleep deprivation may result in aching muscles, blurred vision, and clinical depression, and constipation, dark circles under the eyes, daytime drowsiness, and decrease mental activity and concentration, delirium, dizziness, fainting, hallucination, hand tremor, headache, hypertension, irritability, loss of appetite, memory lapses or loss, nausea, nystagmus, pallor, psychosis-like symptoms, severely yawning, sleep paralysis while awake, slowed reaction time, slowed wound healing, synaesthesia, temper tantrum in children, weakened immune system, weight loss, diabetes mellitus type II, obesity without weight gain and death (Gotlieb et al., 2005).