Résumé
This study investigated the effects of streptozotocin [STZ]-induced diabetes mellitus [DM] on protein and cation levels in ocular tissues [lenses, cornea, lacrimal glands and retina with sclera] of rats. Diabetic rats and their lacrimal glands weighed significantly less [p < 0.05] than age-matched controls. Diabetic animals also had significantly [p < 0.05] elevated blood glucose and significantly reduced [p < 0.05] plasma insulin compared to controls. Total protein concentrations in the cornea, lens, lacrimal gland and retina with sclera were markedly reduced compared to controls [circa 50%-90%]. Diabetic cornea, lenses, lacrimal glands, and retina with sclera contained more Ca[2+] [p < 0.05] than age-matched controls [2-3 fold]. Levels of Zn[2+] werealso elevated [p < 0.05] in the cornea and retina with sclera of diabetic rats, as compared to control rats [2-3 fold], but were unaffected in lenses and lacrimal glands. In contrast, levels of Cu[2+], Mg[2+], Na[+] and K[+] were significantly reduced [p < 0.05] in all ocular tissues of diabetic rats when compared to control animals [circa 30%-70%]. These results show that STZ-induced DM is generally associated with significant physiochemical changes in ocular tissues of rats with changes observed in body weight, blood glucose, and insulin levels and protein and cation concentrations compared to healthy age-matched controls. Based on these data, it has been speculated that diabetes may induce changes in ocular tissues that include: higher protein turnover through increased protease activity and changes in Na[+] / K[+] channel function. It is suggested that these changes may be associated with diabetic retinopathy, diabetic cornea and sight impairment
Résumé
Diabetes mellitus [DM] is a major global health problem and it currently affects more than 175 million people worldwide. DM is an increasingly common chronic disorder which is associated with substantial costs in terms of life and demand on health budgets. Thus, up to 15% of national budgets are spent on the diagnosis, treatment and caring of diabetic patients in the Western World. DM is divided into two main groups, Type 1 or Insulin -dependent diabetes mellitus [IDDM; 5-10 % of all cases and juvenile onset] and Type 2 or Non-insulin- dependent diabetes mellitus [NIDDM; 90-95 % of all cases and adult in onset]. Both Types 1 and 2 DM are associated with a number of common symptoms and long term complications. One of these is the indigestion of food stuffs, especially carbohydrates. This is due to the inability of the gastrointestinal tract, especially the salivary glands and the exocrine pancreas to secrete an adequate amount of the major digestive enzyme, amylase. The medical term used to describe the dysfunction is digestive insufficiency or exocrine pancreatic insufficiency when dealing with the pancreas alone. Current evidence in the literature suggests that exocrine pancreatic insufficiency may be associated with a number of physiological and biochemical processes which may be deranged in the pancreas. These include reduced endogenous insulin secretion or insensitivity of the islet hormone to regulate glucose metabolism especially by pancreatic acinar cells, reduced gene expression for the mRNA amylase and the synthesis and release of the enzyme, reduced cytosolic concentrations of calcium [ca2+] and magnesium [Mg2] Na+ - k+ -ATP pase and tyrosine kinase activities and insensitivity of cholecystokinin [CCK] receptors on pancreatic acinar cells. This review describes the cellular mechanism of exocrine pancreatic insufficiency in DM compared to healthy conditions. The work focuses on a brief review of DM, the normal anatomy and physiology of the pancreas, stimulus-secretion coupling and the interactions between secretagogues, DM-induced exocrine pancreatic insufficiency and the roles of a number of cellular mediators in the stimulus- secretion coupling processes, the cellular and molecular mechanisms associated with the disease and finally, on the scope for future research studies
Résumé
Diabetes mellitus [DM] is the most common of the endocrine disorders and represents a global health problem. DM is characterized by chronic hyperglycaemia due to relative or absolute lack of insulin or the actions of insulin. Insulin is the main treatment for patients with type 1 DM and it is also important in type 2 DM when blood glucose levels cannot be controlled by diet, weight loss, exercise and oral medications alone. Prior to the availability of insulin, dietary measures, including the traditional medicines derived from plants, were the major form of treatment. A multitude of plants have been used for the treatment of diabetes throughout the world. One such plant is Momordica charantia [linn Family: Cucurbaceae] whose fruit is known as Karela or bittergourd. For a long time, several workers have studied the effects of this plant in DM. Treatment with M. charantia fruit juice reduced blood glucose levels, improved body weight and glucose tolerance. M. charantia fruit juice can also inhibit glucose uptake by the gut and stimulate glucose uptake by skeletal muscle cells. Moreover, the juice of this plant preserves islet beta cells and beta cell functions, normalises the systolic blood pressure, and modulates xenbiotic metabolism and oxidative stress. M. charantia also has anti-carcingenic properties. In conclusion, M. charantia has tremendous beneficial values in the treatment of DM