ABSTRACT
This study was designed to investigate the alterations of substance P (SP) and its correlation with apoptosis of the retinal neurons in diabetic rats. The study was carried out with diabetic rats induced by streptozotocin. Changes of SP and its mRNA were examined using enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction. The effect of restoration of SP level by capsaicin (20mg/kg, s.c.) on the apoptosis of the retinal cells was studied. The apoptosis was evaluated by change of ratio of the apoptotic cells and caspase-3 activity in the retina. It was found that increase in apoptosis of retinal cells, by 3.5 fold of control, was accompanied by reduction of SP, by 28% in protein and 32% in the mRNA in the retina at 10 weeks of induction of diabetes, compared to the controls. Capsaicin significantly elevated endogenous SP, by 29% in the mRNA and 17% in protein in the retina, with marked inhibition of the apoptosis and the activity of caspase-3 in the diabetic rats. Induction of diabetes leads to the increase of cell apoptosis and the decrease of SP in the retina. The reduction of the endogenous SP and the increase of the cell apoptosis in the retina of the diabetic rats were reversed by pretreatment with capsaicin. Restoration of SP in the retina may be a novel option for prevention of the retinal injury during development of diabetes.
Subject(s)
Apoptosis , Diabetes Mellitus, Experimental/metabolism , Diabetic Retinopathy/metabolism , Retina/pathology , Substance P/metabolism , Animals , Capsaicin/pharmacology , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/pathology , Gene Expression/drug effects , Male , Rats , Rats, Sprague-Dawley , Retinal Ganglion Cells/metabolism , Substance P/geneticsABSTRACT
Evidence indicates that adaptive responses to systemic stress occur in retina, as indicated by the changes in sympathetic and sensory afferent neurotransmitters in the retina when under stressful stimulation, such as acute myocardial infarction. The aim of this study was to investigate the potential association of the adaptive responses with retina injury, indicated as apoptosis of retinal cells of the rats suffering from acute stress evoked by coronary artery occlusion (CAO). The apoptotic rate of retinal cells and activity of caspase-3 in retina were examined and analyzed over 6 h of CAO using TUNEL and caspase assay. It was observed that the rate of apoptosis of the retinal cells was significantly increased to 16.8%±6% (n=10, vs. control, p<0.05) and 26.9%±6.1% (n=10, vs. control, p<0.05), mainly in ganglion cells of the retina, at 3 and 6h of CAO, respectively. And the activity of caspase-3 was also up-regulated to 2.16±0.77 at 3h of CAO (vs. 1.00±0.32 of the control, p<0.05, n=10) and 2.72±1.11 at 6h of CAO (vs. 1.37±0.76 of control, p<0.05, n=10). The findings may indicate that the adaptive responses to acute stressful simulation, such as acute myocardial infarction, could result in retinal cell injury, presented as increase in apoptosis of retinal cells.
Subject(s)
Apoptosis/physiology , Myocardial Infarction/pathology , Myocardial Infarction/physiopathology , Neurons/physiology , Retina/pathology , Animals , Caspase 3/metabolism , Cell Count/methods , Disease Models, Animal , Male , Rats , Rats, Sprague-DawleyABSTRACT
Evidence indicates that sympathetic nerves and substance P (SP) are involved in some physiological and pathophysiological changes and activities in retina. The aim of this study was to investigate whether SP participates in the stress reaction and possible involvement of adrenergic mechanisms in modulation of the changes of SP in the retina of the rats suffering from acute stress evoked by coronary artery occlusion (CAO). The changes of SP in retina were examined and analyzed within 6h of CAO using immunohistochemistry, in situ hybridization and EIA approaches. The effects of phentolamine, an antagonist of alpha1-adrenergic receptor, and esmolol, an antagonist of beta1-adrenergic receptor, on the changes of SP were investigated to examine the role of adrenergic mechanisms in modulation of expression of SP in the retina under the stressful condition. It was observed that SP was markedly up-regulated in the layers of ganglion cells, inner plexiform, inner nuclear and pigment epithelium within 6h of the CAO. Intravenous administration of the adrenergic antagonists attenuated the up-regulation of SP. The results may indicate that SP in retina was involved in the stress response induced by acute myocardial ischemia. Adrenergic mechanisms may modulate the process in the retina.
Subject(s)
Myocardial Ischemia/pathology , Retina/metabolism , Substance P/metabolism , Up-Regulation/physiology , Adrenergic alpha-Antagonists/pharmacology , Adrenergic beta-Antagonists/pharmacology , Animals , Disease Models, Animal , Male , Phentolamine/pharmacology , Propanolamines/pharmacology , Protein Precursors/genetics , Protein Precursors/metabolism , Rats , Rats, Sprague-Dawley , Retina/drug effects , Retina/pathology , Substance P/genetics , Tachykinins/genetics , Tachykinins/metabolism , Time Factors , Up-Regulation/drug effectsABSTRACT
OBJECTIVE: In order to prove a basis for rational exploitation and utilization of the herb, the charaeteristic feature for Acanthus iliciflius was studied. METHOD: The botanical and pharmacognostic features of the collected original plant were stadied. RESULT: A. ilicifolius showed obvious pharmacognostic characters. The aerate cells of the root were upgrowth. and four vascular bundles were found in leaf venation. CONCLUSION: The distinct characteristic features revealed in this studies can serve as evidence for the identification of A. ilicifolius.
