Browsing by Author "Omolaoye, Temidayo Siyanbola"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    The Possible Ameliorating effects of Rooibos, Honeybush and Sutherlandia on diabetes-induced reproductive impairment in adult male Wistar rats
    (Stellenbosch : Stellenbosch University, 2020-03) Omolaoye, Temidayo Siyanbola; Du Plessis, Stefan; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Medical Physiology.
    ENGLISH ABSTRACT: The global prevalence of infertility is on the rise, and so is male factor infertility. Out of the approximately 72.4 million infertile couples worldwide, male factor is responsible for 50%. It has been reported that sperm quality is on the decline, even in healthy men. Several aetiologies have been identified, and this includes disease-related male infertility, such as diabetes mellitus (DM). DM is a chronic non-communicable disease, marked by increased hyperglycaemia which occurs as a result of lack in insulin secretion or due to the insensitivity of the target tissue to the metabolic effect of insulin. It has been reported that 422 million people are affected with DM globally, of which ≤10% is type 1 diabetic and ≤90% is type 2. Studies have shown that although most autoimmune diseases usually affect a higher percentage of women, type 1 diabetes is more prevalent in boys and men. The consequential detrimental effects of DM on male fertility have been reported in both experimental animals and diabetic men. This includes, decreased sperm motility, reduced normal sperm morphology, increased fragmented spermatozoa and many more defects. In the course of unravelling the pathways through which DM affect male fertility, studies have elucidated the role of endocrine dysfunction, formation of reactive oxygen species (ROS) and the subsequent development of oxidative stress (OS). However, other possible related pathways such as the involvement of glycated proteins, are yet to be explored. Since there are evidences that DM is detrimental to male fertility, it is important to firstly understand the underlying pathophysiology and then develop and explore strategies to combat this disease and its associated male reproductive complications. Many natural and artificial agents have been proposed to have antioxidant properties due to their potential in reducing oxidation. Antioxidants work either by scavenging ROS or by preventing its formation. Rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia) and sutherlandia (Lessertia frutescens) are plants endemic to Southern Africa. Herbal teas are derived from the leaves and stems of these plants. These infusions have been shown to be caffeine-free. Studies have also reported that the infusions from these plants contain bioactive chemical compounds with therapeutic benefits. Additionally, studies have shown their beneficial role in preventing the development of diseases and some have shown their ameliorative effects. However, their role in male reproduction is little understood as this represents the first study to report the effects of honeybush and sutherlandia on male reproductive function. Based on the expressed gaps in knowledge, the study was divided into two main parts, with each having several objectives. For the first part, thirty adult male rats were randomly divided into three groups of ten, which included a vehicle and two streptozotocin (STZ) groups receiving either 30mg/kg (STZ30) or 60mg/kg (STZ60) intraperitoneally. For the second part, ninety animals were divided into nine groups of ten without bias. The groups included a control (water only), vehicle (STZ control, citrate buffer + water), rooibos (2% fermented rooibos), honeybush (4% fermented honeybush), sutherlandia (0.2% unfermented sutherlandia), diabetic control (STZ45mg/kg + water), diabetic + rooibos (STZ45mg/kg + 2% rooibos), diabetic + honeybush (STZ45mg/kg + 4% honeybush), and diabetic + sutherlandia (STZ45mg/kg + 0.2% sutherlandia) group. Animals in the diabetic infusion treated groups were pre-treated with the respective infusion one week before DM induction. Animals were monitored closely throughout the treatment period and were sacrificed seven weeks after DM induction. Blood, testes and epididymides were collected for further analysis.The results of the first part of this study showed the negative effects of DM on male reproductive function, as diabetic animals presented with a decrease in spermatozoa with normal morphology and an increased number of spermatozoa with a higher deformity index. Histological and histomorphometrical analysis of the testis showed alteration in the seminiferous tubules’ cellular association in diabetic animals. Additionally, the first section further sheds some light on the involvement/expression of advanced glycation end products (AGE), its receptor (RAGE), mitogen-activated protein kinases and the activation of apoptosis in diabetes, which may contribute to the impairment seen in male fertility. Briefly, in DM, there is altered antioxidant enzyme activity (↓Catalase) which may result in OS. The development of OS can on the one hand instigate the breakdown of polyunsaturated fatty acids (PUFA), which can be measured by the levels of malondialdehyde (MDA) and also indirectly increase AGE formation. The peroxidation of PUFAs attracts more ROS formation, which can activate apoptotic induction, resulting in impaired sperm function. AGEs work by binding to their receptor (RAGE). The AGE-RAGE complex initiates the activation of the MAPKs, which may induce apoptosis by increasing the cleavage of PARP, hence resulting in nDNA damage. All these effects collectively result in reduced male fertility. To properly understand the role of the infusions (rooibos, honeybush and sutherlandia) on male reproduction of both healthy and diabetic animals, the second part of the study was divided into four sub-studies. Subsection one of the second part of the study investigated whether treatment with rooibos, honeybush and sutherlandia will impact sperm functional parameters positively or otherwise, in healthy rats. Animals treated with the respective infusions presented with a percentage increase in SOD activity but showed reduced sperm motility and decreased normal The results of the first part of this study showed the negative effects of DM on male reproductive function, as diabetic animals presented with a decrease in spermatozoa with normal morphology and an increased number of spermatozoa with a higher deformity index. Histological and histomorphometrical analysis of the testis showed alteration in the seminiferous tubules’ cellular association in diabetic animals. Additionally, the first section further sheds some light on the involvement/expression of advanced glycation end products (AGE), its receptor (RAGE), mitogen-activated protein kinases and the activation of apoptosis in diabetes, which may contribute to the impairment seen in male fertility. Briefly, in DM, there is altered antioxidant enzyme activity (↓Catalase) which may result in OS. The development of OS can on the one hand instigate the breakdown of polyunsaturated fatty acids (PUFA), which can be measured by the levels of malondialdehyde (MDA) and also indirectly increase AGE formation. The peroxidation of PUFAs attracts more ROS formation, which can activate apoptotic induction, resulting in impaired sperm function. AGEs work by binding to their receptor (RAGE). The AGE-RAGE complex initiates the activation of the MAPKs, which may induce apoptosis by increasing the cleavage of PARP, hence resulting in nDNA damage. All these effects collectively result in reduced male fertility. To properly understand the role of the infusions (rooibos, honeybush and sutherlandia) on male reproduction of both healthy and diabetic animals, the second part of the study was divided into four sub-studies. Subsection one of the second part of the study investigated whether treatment with rooibos, honeybush and sutherlandia will impact sperm functional parameters positively or otherwise, in healthy rats. Animals treated with the respective infusions presented with a percentage increase in SOD activity but showed reduced sperm motility and decreased normal The results of the first part of this study showed the negative effects of DM on male reproductive function, as diabetic animals presented with a decrease in spermatozoa with normal morphology and an increased number of spermatozoa with a higher deformity index. Histological and histomorphometrical analysis of the testis showed alteration in the seminiferous tubules’ cellular association in diabetic animals. Additionally, the first section further sheds some light on the involvement/expression of advanced glycation end products (AGE), its receptor (RAGE), mitogen-activated protein kinases and the activation of apoptosis in diabetes, which may contribute to the impairment seen in male fertility. Briefly, in DM, there is altered antioxidant enzyme activity (↓Catalase) which may result in OS. The development of OS can on the one hand instigate the breakdown of polyunsaturated fatty acids (PUFA), which can be measured by the levels of malondialdehyde (MDA) and also indirectly increase AGE formation. The peroxidation of PUFAs attracts more ROS formation, which can activate apoptotic induction, resulting in impaired sperm function. AGEs work by binding to their receptor (RAGE). The AGE-RAGE complex initiates the activation of the MAPKs, which may induce apoptosis by increasing the cleavage of PARP, hence resulting in nDNA damage. All these effects collectively result in reduced male fertility. To properly understand the role of the infusions (rooibos, honeybush and sutherlandia) on male reproduction of both healthy and diabetic animals, the second part of the study was divided into four sub-studies. Subsection one of the second part of the study investigated whether treatment with rooibos, honeybush and sutherlandia will impact sperm functional parameters positively or otherwise, in healthy rats. Animals treated with the respective infusions presented with a percentage increase in SOD activity but showed reduced sperm motility and decreased normal morphology. Paradoxically, they presented with increased sperm concentrations. Hence, rooibos, honeybush and sutherlandia may enhance sperm concentration, which represents the sperm quantity. However, they may impair sperm quality (sperm motility and morphology), when consumed by healthy animals. Subsection two of the second part of the study investigated the testicular oxidative stress and apoptosis status in diabetic rats following treatment with rooibos, honeybush and sutherlandia infusions. This section highlighted the negative impact of DM on sperm functional parameters through increased lipid peroxidation and reduced antioxidant activity. The infusion treatment groups displayed increased antioxidant enzyme activity, which may be partly responsible for the observed improvement in sperm motility and morphology of diabetic animals receiving rooibos (DRF) and diabetic animals receiving sutherlandia (DSL). Additionally, the current study have shown the increased expression of apoptotic biomarkers in the diabetic control (DC) animals, which were not alleviated by the infusions. This suggests that these infusions play a role in alleviating diabetes-induced sperm function impairment through suppression of OS, but their role in apoptosis is still unclear. Subsection three of the second part of the study investigated the role of rooibos, honeybush and sutherlandia on insulin signalling in the testes of diabetic rats. All diabetic groups presented with a significant increase in blood glucose levels after diabetes induction. However, the diabetic animals treated with the infusions showed only a mild decrease in fasting blood glucose. The diabetic control animals showed a decrease in testis protein expression of IRS-1, PkB/Akt and GLUT4. Diabetic animals treated with rooibos (DRF) and honeybush (DHB) displayed an upregulation in IRS-1, while diabetic animals treated with sutherlandia (DSL) showed improvement indecrease in PkB/Akt, DHB and DSL animals displayed upregulation compared to control. All diabetic animals showed increased phosphorylated ERK1/2 and reduced total ERK1/2 when compared to control and vehicle. Additionally, diabetic control animals presented with a non significant decrease in plasma testosterone concentration compared to control, while DRF and DSL showed a significant decrease and DHB showed upregulation. This suggests that (i) the activation of IRS, PkB/Akt, ERK and GLUT translocation is important in testicular insulin signalling (ii) rooibos, honeybush and sutherlandia may play a role in testicular insulin signalling, however, through different pathways (iii) honeybush may mildly enhance testosterone production in diabetes. Lastly, the fourth subsection of the second part of the study investigated the descriptive histological evaluation of the testis and cauda epididymis after treating with rooibos, honeybush and sutherlandia in both healthy and diabetic rats. The infusion control groups (RF, HB and SL) showed normal seminiferous tubule cellular association, presence of spermatozoa in the epididymal lumen and normal overall architecture. Both the testicular and epididymal morphology were altered in DM, but these disruptions were mildly alleviated by rooibos, honeybush and sutherlandia. It appears, from appreciating the results of the entire study, that diabetes does have detrimental effects on male reproduction, both at the tissue and cellular levels. The cellular impact may be exerted through protein glycation, development of OS and apoptosis induction. The use of rooibos, honeybush and sutherlandia, when healthy, should be taken moderately and with caution, as too much may be detrimental and may impair sperm functional parameters. However, in disease conditions such as diabetes, these infusions may be beneficial, as: (i) Rooibos and sutherlandia may mildly improve sperm quality (motility and morphology), (ii) Rooibos, honeybush and sutherlandia may mildly reduce hyperglycaemia by enhancing insulin signalling, (iii) Honeybush may enhance testosterone production, (iv) Rooibos, honeybush and sutherlandia may mildly improve the histomorphological architecture of the seminiferous tubule and cauda epididymal tubule.