3. Electronic Theses and Dissertations (ETDs) - All submissions
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/45
Browse
Search Results
Item Effects of S-ALLYL-L-cysteine on high-fructose diet-induced neonatal metabolic programming in wistar rats(2017) Lembede, Busisani WisemanThe consumption of fructose during the perinatal period programmes for increased susceptibility to developing metabolic derangements immediately in childhood or later in adulthood. S-allyl-cysteine (SAC), a phytochemical constituent of garlic, has antioxidant, antidiabetic and antihyperlipidaemic properties. We hypothesised that neonatal orally administered SAC could protect against the development of high-fructose diet-induced metabolic derangements in both early and adult life. The study was undertaken in two major experiments. In the first experiment, the potential of neonatal oral administration of SAC to protect against acute metabolic derangements induced by high-fructose diet consumption in early-life was investigated. Sixty-four suckling (male = 32; female = 32) 4-day old Wistar rat pups were randomly allocated to and administered the following treatment regimens daily for 15 days: group I - 10 ml/kg distilled water (DH), group II - 10 ml/kg 20% fructose solution (FS), group III - 150 mg/kg body mass per day SAC, and group IV - (SAC + FS). On postnatal day 21 the pups’ blood cholesterol, glucose and triglyceride concentrations were determined. Immediately thereafter the pups were euthanised and tissues collected for analyses. Neonatal orally administered SAC significantly increased (p < 0.05) the plasma insulin concentration in male pups. The oral administration of a 20% FS decreased (p < 0.05) plasma insulin in the female pups. However, the anti-insulinotropic effect of a 20% FS in female rat pups was attenuated by orally administered SAC. Neonatal orally administered SAC showed insulinotropic effects in male rat pups and protected female rat pups against the anti-insulinotropic effect of a 20% FS. The second experiment investigated the potential of neonatal orally administered SAC to protect against high-fructose diet-induced metabolic derangements later in adulthood. One hundred and twenty-eight (males = 64; females = 64), 4-day old Wistar rat pups were randomly allocated to and administered treatment regimens as described for the first experiment. On postnatal day 21, the pups were weaned and allowed to grow on a standard rat chow (SRC) until postnatal day 56. The rats from each treatment regimen were then randomly split into two subgroups: one on a standard rat chow (SRC) and plain drinking water and another on SRC and 20% fructose drinking water and then subjected to these treatment regimens for eight weeks after which they were then euthanised and tissues collected for analyses. Neonatal orally administered 20% FS alone, programmed male and female rats to have increased (p < 0.05) liver lipid accretion in adulthood. The neonatal oral administration of SAC attenuated the programming of increased liver lipid accretion in adulthood induced by neonatal orally administered 20% FS. Thus neonatal oral administration of SAC could potentially protect against neonatal fructose consumption programming of fatty-liver related metabolic dysfunctions in adult life.Item The effect of ischaemia and reperfusion on discharge patterns of nociceptive afferent nerve fibres in the rat tail(2017) Dal Mas, IlarioIn rats anaesthetised with enflurane, Iexamined.the response of coccygeal primary afferents fibres to noxious thermal and mechanical stimulation and to innocuous brushing, during transient ischaemia and reperfusion of their receptive fields on the tail. Ischaemia was induced by occluding the blood supply to the tail for 30 min using a tourniquet. I discovered four different groups of afferent fibres, distinguished by conduction velocity and modality, A{3fibres responding to both brush and pinch of their receptive fields showed decreased sensitivity to brush during both ischaemia and reperfusion; Ao fibres responding to pinch were unaffected by either ischaemia or reperfusion, C fibres responding to noxious heat (49· C) and pinch showed hypersensitivity during reperfusion, especially immediately after release of the tourniquet. Another group of C fibres, presumably chemosensitive, became more actiVA during ischaemia and exhibited a 7-fold increase in firing rate during receptive field reperfuslon in the absence of obvious stimuli. These results indicate that during reperfuslon of the rat tail following transient ischaemia, myelinated fibres do not increase their input to the CNS, while C fibres became more active and showed sensitization to noxious stimulation of their receptive fields. The enhanced CNS nociceptive activity which occurs during reperfusion consequently results from both peripheral and. central sensitization.