Quantitative evaluation of pulomnary neuroendocrine cells and the role of nitric oxide in experimentally induced renovascular hypertension in male albino rats

Renovascular hypertension is the most common cause of secondary hypertension that leads to disorders in many systems and organs including the lung. The present work was carried out to determine how experimentally induced renovascular hypertension affects rat lung tissue with a special focus on the disorders in nitric oxide [NO] production as well as the number of pulmonary neuroendocrine cells. Twenty-one adult male albino rats were used; they were divided into three groups. Group I included five control rats, group II included eight rats that were sham operated, and group III included eight rats that were subjected to a renovascular hypertension procedure. Lower segments of the right lung lobes were obtained and then subjected to H and E and Masson's trichrome stains. Endothelial nitric oxide synthase [eNOS] and calcitonin antibody-2 were also used as immunohistochemical stains. Morphometric measurements included the area% of collagen fibers, the optical density of eNOS immunoreaction, and the number of calcitonin-positive neuroendocrine cells. Data were recorded and analyzed statistically. In group III, H and E-stained sections showed thickening of the tunica media of pulmonary arteries and alveolar walls with predominantly type II pneumocytes. Consequently, the thickened arteries showed a significant increase in the mean area% of collagen fibers, together with a significant decrease in the mean optical density of eNOS immunoreactivity when compared with the control group. The mean number of calcitonin immunoreactive neuroendocrine cells of group III showed a significant increase versus the control group. The current study showed an increased number of pulmonary neuroendocrine cells with renovascular hypertension. This increase may represent a compensatory mechanism to overcome renovascular hypertension. Thus, clinical trials could be conducted to prove the possible role of calcitonin-producing pulmonary neuroendocrine cells in controlling renovascular hypertension

Assessment of rat endometrial pinopodes in normal cycles and following HCG ovarian hyperstimulation with or without progesterone supplementation: scanning electron microscopic study

Pinopodes, mushroom-like projections, arise from the endometrial surface at or just before the time of implantation. They have been proposed as a method of identifying endometrial receptivity for transferred embryo in programs of IVF. The present work was planned to assess the expression of pinopodes in rat endometrium in normal cycles and following ovarian hyperstimulation with or without progesterone supplementation as a trial to estimate the optimal date for successful embryo transfer in IVF programs. Forty-five adult female albino rats were divided equally into three groups. In the control group, ovulation was induced by mechanical vagino-cervical stimulation. Group II was subjected to ovarian hyperstimulation using human chorionic gonadotrophin [HCG] 350 IU/kg injected intraperitoneally [two injections 48h apart and vagino-cervical stimulation was performed on the evening of administration of the second injection. Group III was treated in the same way as group II, followed by a daily subcutaneous injection of progesterone 35mg/kg. All rats were sacrificed 3, and 5 days after vagino-cervical stimulation. The middle third of the right uterine horn were processes for scanning electron microscope examination. The mean number of pinopodes was statistically analyzed. In control rats, pinopodes started to appear on day 4 and significantly increased in number on day 5. In the HCG-ovarian hyperstimulated group, there was an early appearance of pinopodes on day 3, which increased in number on day 4 and regressed on day 5. With progesterone supplementation, there was an obvious increase in the number of pinopodes especially on day 4. It could be concluded that ovarian hyperstimulation using HCG may cause early expression of pinopodes and premature formation of an implantation window. Also, progesterone supplementation could enhance endometrial receptivity. This should be taken into consideration in IVF programs to synchronize embryo and endometrial development, which could improve pregnancy rates

Pinopodes

Pinopodes are balloon-like projections that arise from the endometrial surface in mice, rats and humans during the window of receptivity and are best viewed using scanning electron microscopy. Differences are seen in the shape, size and content of pinopodes between rodents and humans. The diameter of pinopodes in rats is 3.0-4.0 microm and in mice and humans it is 6 microm. The percentage of luminal epithelium covered by pinopodes during the window of receptivity varies in rats from 5.5 to 20%, in mice from 0.6 to 20% and in humans from 0 to 12%. The formation of pinopodes in both the rodent and human endometrium appears to be progesterone dependent, whereas administration of estradiol results in their rapid loss. Although the biological function of pinopodes is less well understood, a correlation between the number of pinopodes and implantation rate has been revealed. During implantation, pinopodes interdigitate with microvilli on the syncytiotrophoblast surface of blastocysts. Very few markers have revealed the presence of pinopodes; these include integrins, leukaemia inhibitory factor, heparin-binding epidermal-like growth factor, glutaredoxin, Hoxa-10 and Mucin 1. Clinically, pinopodes are the best studied endometrial factors involved in implantation. In conclusion, pinopodes are a good marker for endometrial receptivity. Further studies other than endometrial biopsy are needed to demonstrate the presence of pinopodes for timing of endometrial receptivity to increase the pregnancy rate in programmes on in-vitro fertilization

Vascular endothelial growth factor [Vegf] localization in the mammary gland at various stages of its physiological cycle; a histological and immunohistochemical study

Vascular Endothelial Growth Factor [VEGF] is a potent angiogenic and vascular permeability enhancing factor under both physiological and pathological conditions including tumor angiogenesis. To study the localization and intensity of VEGF in the mammary gland at various stages of its physiological cycle. Mammary glands from sixty female albino rats were divided intosix groups [10 rats each]: Group I nulliparous, group II early pregnancy, group III late pregnancy, group IV lactating, group V early involution and group VI late involution. Human specimens from five females of variable age [childbearing and post-menopausal] were examined. Animal specimens were subjected to histological study while all specimens were subjected to immunohistochemical detection of VEGF. Morphometric analysis was performed for area% and optical density of positive VEGF reaction. VEGF was detected in epithelial lining of ducts and acini, endothelium of blood vessels as well as some stroma cells and macrophages. It was detected in resting nulliparous rat mammary gland with an increase during early pregnancy that became remarkable in late pregnancy and reached its maximum during lactation. Furthermore, VEGF was also detected in milk within lactating mammary acini. During involution, VEGF decreased progressively and reached a minimum in late involution. Human specimens showed stronger VEGF reaction during childbearing period than in post-menopause. The localization of VEGF in the endothelial cells of blood vessels, epithelium of mammary gland ducts and acini as well as some stroma cells and macrophages denoted that it is secreted by those cells. The increased VEGF in pregnancy and lactation indicates that it plays an important role in the development and function of the manunary gland