الملخص
In Colombia the use of glyphosate commercial formulations (Roundup™) for spraying have left deleterious effects on animals and humans. Much of this spraying takes place at the Orinoco basin, habitat of one of the most exported ornamental fish in Colombia, Cardinal neon. To evaluate the effect of Roundup Activo™ four experimental treatments were carried out with 0 mg/L (T1), 0.1 mg/L (T2), 1 mg/L (T3) and 5 mg/L (T4) during 30 days of exposure. The fishes were processed for high-resolution optical microscopy. The main finding of Roundup Activo™ exposure was an increase in mast cells number in brain blood vessels and some neuronal nuclei of the preoptic and posterior diencephalic areas, including hypothalamus. A correlation between concentrations and mast cells number was observed, with the largest mast cells number in T4 treatment. Mast cells presence is a stress benchmark, suggesting the beginning of allergic, inflammatory and apoptotic events. Presence of mast cells in these brain areas may lead to alterations on reproduction, visual and olfactory information integration among other processes. These alterations may result in diminished survival, affecting the conservation of this species in its natural habitat.(AU)
En Colombia, el uso de formulaciones comerciales de glifosato (Roundup™) para la fumigación ha producido efectos nocivos en animales y humanos. Gran parte de esta fumigación se realiza en la cuenca del Orinoco, hábitat de uno de los peces ornamentales más exportados de Colombia, el Neón Cardenal. Para evaluar el efecto de Roundup Activo™ se realizó un experimento con cuatro tratamientos 0 mg/L (T1), 0,1 mg/L (T2), 1 mg/L (T3) y 5 mg/L (T4) durante 30 días. Los peces fueron procesados para microscopía óptica de alta resolución. El principal hallazgo fue el aumento del número de mastocitos en los vasos sanguíneos cerebrales y algunos núcleos neuronales del área preóptica y diencefálica posterior, incluido el hipotálamo. Identificamos una correlación entre las concentraciones y el número de mastocitos, que alcanzó su máximo en T4. La presencia de mastocitos evidencia estrés, promoviendo eventos alérgicos, inflamatorios y apoptóticos. La presencia de mastocitos en estas áreas del cerebro puede llevar a alteraciones en la reproducción e integración de la información visual y olfativa entre otros procesos. Estas alteraciones pueden resultar en una disminución de la supervivencia, afectando la conservación de esta especie en su hábitat natural.(AU)
الموضوعات
Animals , Characiformes/physiology , Mast Cells/cytology , Herbicidesالملخص
OBJECTIVE@#To investigate the diagnostic significance of basophil activation test (BAT) in anaphylaxis to non-ionic contrast media through testing the content of CD63, mast cell-carboxypeptidase A3 (MC-CPA3), and terminal complement complex SC5b-9 of the individuals by testing their levels in the normal immune group and the anaphylaxis groups to β-lactam drugs and non -ionic contrast media.@*METHODS@#The CD63 expression of basophilic granulocyte in blood was detected by flow cytometry. The levels of MC-CPA3 in blood serum and SC5b-9 in blood plasma were detected by ELISA.@*RESULTS@#The CD63 expression of basophilic granulocyte in blood, the levels of MC-CPA3 and SC5b-9 of anaphylaxis to non-ionic contrast media and β-lactam drugs were significantly higher than that in normal immune group (P < 0.05).@*CONCLUSION@#There is activation of basophilic granulocytes, mast cells and complement system in anaphylaxis to non-ionic contrast media. BAT can be used to diagnose the anaphylaxis to non-ionic contrast media.
الموضوعات
Humans , Anaphylaxis/diagnosis , Basophils/cytology , Carboxypeptidases A/metabolism , Complement Membrane Attack Complex/metabolism , Contrast Media , Flow Cytometry , Granulocytes/cytology , Mast Cells/cytology , Tetraspanin 30/metabolismالملخص
PURPOSE: The purpose of this study was to evaluate the effects of essential oil on oxidative stress, immunity, and skin condition in atopic dermatitis (AD) induced mice. METHODS: This study was a 3x3 factorial design. Factors were oil type (Lavender, Thyme, and 2:1 mixture of lavender and thyme oil [blending oil]) and treatment period (0 day, 7 days, and 21 days). The samples were 45 mice with AD and randomly assigned to nine groups of five mice per group. The dependent variables such as superoxide radical, IgE, degranulated mast cells, and epidermal thickness were measured. Data were collected from February to April in 2014. Descriptive statistics, One-way ANOVA, Two-way ANOVA, and Tukey's HSD test were performed using the SPSS WIN 20.0 program. RESULTS: Dependent variables were not statistically significantly different by the three oil types (p >.05). Essential oils such as lavender, thyme, and blending oil were all effective in reducing AD symptoms and especially 2:1 blending oil were most effective. There were statistically significant differences by the three treatment periods in all dependent variables (p <.001). There were statistically significant interactions between oil types and treatment periods in all dependent variables (p <.01). For decreasing superoxide radical, degranulated mast cells, and epidermal thickness, 2:1 mixed oil should be applied for at least 21 days. Otherwise to reduce IgE, 2:1 mixed oil should be used for at least 7 days. CONCLUSION: These findings provide bases for developing effective interventions for AD patients to manage their AD symptoms.
الموضوعات
Animals , Mice , Dermatitis, Atopic/chemically induced , Disease Models, Animal , Immunity/drug effects , Immunoglobulin E/blood , Lavandula/chemistry , Mast Cells/cytology , Oils, Volatile/chemistry , Oxidative Stress/drug effects , Picryl Chloride/toxicity , Plant Oils/chemistry , Singlet Oxygen/metabolism , Skin/drug effects , Thymus Plant/chemistryالملخص
Los mastocitos o células cebadas son células que se hallan ampliamente distribuidas en todos los tejidos, principalmente en la piel y en las superficies mucosas cerca de los vasos sanguíneos y linfáticos. Pueden ser activadas por diversos estímulos de origen inmunitario o no inmunitario, liberando un amplio espectro de mediadores que incluyen histamina, proteasas, citoquinas, factores de crecimiento y metabolitos del ácido araquidónico. Estas moléculas juegan un importante papel en numerosos procesos fisiológicos y patológicos. La función mejor conocida de los mastocitos es la defensa contra infestaciones parasitarias; sin embargo, son importantes en la defensa del huésped a través de su participación en la inmunidad innata y adaptativa. Median la respuesta inflamatoria, la remodelación de los tejidos y la angiogénesis. Intervienen en las reacciones de hipersensibilidad tipo I y tienen un papel contradictorio en la progresión tumoral. En esta revisión se analiza el origen, la distribución y las funciones de los mastocitos en condiciones fisiológicas y en distintas enfermedades humanas.
الموضوعات
Mast Cells/cytology , Mast Cells/classification , Mast Cells/physiology , Mast Cells/metabolism , Neoplasmsالملخص
Introduction: Oral submucous fibrosis (OSMF) is a chronic, progressive, scarring disease that predominantly affects the people of south-east Asian origin. Aim: The present study is aimed at comparing and correlating the mast cell density (MCD) and micro vascular density (MVD) in normal mucosa and different grades of OSMF and to analyze their role in the disease progression. Materials and Methods: MCD was assessed immunohistochemically using anti mast cell tryptase and MVD was assessed using anti-factor VIII related von Willebrand factor. Results: The one way comparison of MVD and MCD in normal mucosa and among different grades of OSMF showed a significant increase in MCD and MVD among OSMF cases. Correlation analysis using Pearson correlation coefficient, showed positive correlation between MCD and MVD i.e. as MCD increases there is an exponential increase in MVD. Conclusion: The increase in MVD and MCD reveals their role in the pathogenesis of OSMF, a lesion characterized by progressive fibrosis in early stages and failure of degradation or remodeling in the advanced stages.
الموضوعات
Case-Control Studies , Cell Proliferation , Endothelial Cells/cytology , Humans , Immunohistochemistry , Mast Cells/cytology , Microcirculation , Mouth Mucosa/blood supply , Mouth Mucosa/cytology , Neovascularization, Pathologic/pathology , Oral Submucous Fibrosis/classification , Oral Submucous Fibrosis/pathology , Reference Valuesالملخص
The correlation between microvessel density and mast cells density in canine mammary tumors was studied. Sixty-five samples of canine mammary tumors, being 24 benign and 41 malignant, were analyzed. The routine Toluidine Blue staining method was used to assess the mast cells. To evaluate angiogenesis, the immunohistochemical expression of CD31 was assessed. There was no significant difference in either mast cells (P=0.44) or microvessel density (P=0.77) between malignant and benign tumors. A positive correlation was observed between microvessel density and mast cells (r=0.39; P=0.011) in malignant tumors. These results suggest that mast cells may play a role in canine mammary malignant tumors development, promoting angiogenesis, similar to some tumors described in the human species.
Estimou-se a correlação entre a densidade de microvasos e a densidade de mastócitos em tumores mamários caninos. Sessenta e cinco amostras de tumores mamários caninos - 24 benignos e 41 malignos - foram analisadas, pela técnica rotineira de coloração com Azul de Toluidina para avaliação da densidade de mastócitos. Para a avaliação da angiogênese, foi utilizada a técnica de imunoistoquímica para expressão de CD31. Não foram observadas diferenças significativas de mastócitos (P=0.44) ou densidade microvascular (P=0.77) entre tumores malignos e benignos. A correlação entre densidade microvascular e densidade de mastócitos foi positiva (r=0,39; P=0,011) em tumores malignos. Estes resultados sugerem que os mastócitos podem exercer um importante papel no desenvolvimento de tumores mamários malignos caninos mediante promoção da angiogênese, similarmente a alguns tumores descritos na espécie humana.
الموضوعات
Animals , Dogs/classification , Mammary Neoplasms, Animal , Tolonium Chloride/administration & dosage , Mast Cells/cytologyالملخص
Mast cells have been regarded for a long time as effector cells in IgE mediated type I reactions and in host defence against parasites. However, they are resident in all environmental exposed tissues and express a wide variety of receptors, suggesting that these cells can also function as sentinels in innate immune responses. Indeed, studies have demonstrated an important role of mast cells during the induction of life-saving antibacterial responses. Furthermore, recent findings have shown that mast cells promote and modulate the development of adaptive immune responses, making them an important hinge of innate and acquired immunity. In addition, mast cells and several mast cell-produced mediators have been shown to be important during the development of allergic airway diseases. In the present review, we will summarize findings on the role of mast cells during the development of adaptive immune responses and highlight their function, especially during the development of allergic asthma.
الموضوعات
Animals , Humans , Mice , Anti-Infective Agents/pharmacology , Asthma/immunology , Cytokines/metabolism , Histamine/metabolism , Hypersensitivity/immunology , Immune System , Immunoglobulin E/immunology , Leukotrienes/metabolism , Mast Cells/cytology , Models, Biological , Prostaglandins/metabolism , Tumor Necrosis Factor-alpha/metabolismالملخص
PURPOSE: Postinfectiously irritable bowel syndrome (PI-IBS) develops in 3-30% of individuals with bacterial gastroenteritis. Recent studies demonstrated increases in inflammatory components in gut mucosa of PI-IBS patients even after complete resolution of infection. We aimed to investigate histological changes in colon and rectum of PI-IBS subjects after long term period of infection. MATERIALS AND METHODS: We recruited PI-IBS subjects who had been diagnosed IBS after complete resolution of enteritis caused by shigellosis outbreak 3 years earlier. We compared unmatched four groups, PI-IBS (n = 4), non PI-IBS (n = 7), D-IBS (n = 7, diarrhea predominant type) and healthy controls (n = 10). All of them underwent colonoscopic biopsy at three areas, including descending colon (DC), sigmoid colon (SC) and rectum, which were assessed for 5-hydroxytryptamine (5-HT)/peptide YY (PYY)-containing enterochromaffin (EC) cell, intraepithelial (IEL) and lamina propria T lymphocyte (CD3), CD8 lymphocytes, mast cells and CD68/calprotectin+ macrophages. RESULTS: All subjects had no structural or gross abnormalities at colonoscopy. In PI-IBS, 5-HT containing EC cells, PYY containing EC cells, IELs, CD3 lymphocytes, CD8 lymphocytes, mast cells, and CD68 + macrophages were increased compared to control (p < 0.05). In D-IBS, PYY containing EC cells, IELs, and CD3 lymphocytes were increased compared to control (p < 0.05). In PI-IBS, 5-HT containing EC cells tended to increase and PYY containing EC cells, CD8 lymphocytes, mast cells, and CD68+ macrophages were increased compared to non PI-IBS (p < 0.05). Calprotectin + marcrophages were decreased in PI-IBS, non PI-IBS and IBS compared to control. CONCLUSION: The immunoendocrine cells were sporadically increased in PI-IBS, non PI-IBS and D-IBS compared with control. Our findings in a very small number of patients suggest that mucosal inflammation may play a role in long-term PI-IBS, and that other sub-groups of IBS and larger scale studies are needed to confirm this observation.
الموضوعات
Adult , Female , Humans , Male , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , CD8-Positive T-Lymphocytes/cytology , Case-Control Studies , Colon, Descending/pathology , Colon, Sigmoid/pathology , Colonoscopy , Dysentery, Bacillary/complications , Enterochromaffin Cells/cytology , Immunohistochemistry , Intestinal Mucosa/pathology , Irritable Bowel Syndrome/metabolism , Macrophages/cytology , Mast Cells/cytology , Peptide YY/metabolism , Rectum/pathology , Serotonin/metabolismالملخص
This study was performed in order to assess whether acute stress can increase mast cell and enterochromaffin (EC) cell numbers, and proteinase-activated receptor-2 (PAR2) expression in the rat colon. In addition, we aimed to investigate the involvement of corticotrophin-releasing factor in these stress-related alterations. Eighteen adult rats were divided into 3 experimental groups: 1) a saline-pretreated non-stressed group, 2) a saline-pretreated stressed group, and 3) an astressin-pretreated stressed group. The numbers of mast cells, EC cells, and PAR2-positive cells were counted in 6 high power fields. In proximal colonic segments, mast cell numbers of stressed rats tended to be higher than those of non-stressed rats, and their PAR2-positive cell numbers were significantly higher than those of non-stressed rats. In distal colonic segments, mast cell numbers and PAR2-positive cell numbers of stressed rats were significantly higher than those of non-stressed rats. Mast cell and PAR2-positive cell numbers of astressin-pretreated stressed rats were significantly lower than those of saline-pretreated stressed rats. EC cell numbers did not differ among the three experimental groups. Acute stress in rats increases mast cell numbers and mucosal PAR2 expression in the colon. These stress-related alterations seem to be mediated by release of corticotrophin-releasing factor.
الموضوعات
Animals , Male , Rats , Colon/metabolism , Corticotropin-Releasing Hormone/antagonists & inhibitors , Enterochromaffin Cells/cytology , Mast Cells/cytology , Peptide Fragments/pharmacology , Rats, Wistar , Receptor, PAR-2/metabolism , Restraint, Physical , Stress, Physiologicalالملخص
Various studies have shown the role of mast cells in chronic inflammatory states and in tumor growth. The study is designed to have an idea of the relationship of mast cell density (MCD) to gastric ulcer and cancer, to verify whether mast cell accumulation occurred in the two conditions especially in Indian patients and thus postulate that therapeutic strategies against mast cell mediators could be useful in treatment. Also, we want to review literature and attempt to explain our findings. A total of 240 patients, who underwent their first endoscopy and biopsy for a span of 21/2 years were studied retrospectively. Out of these, 210 cases that were either gastric ulcers or cancer were chosen for this MCD study. Biopsies were sectioned and stained routinely. Toluidine blue stain and copper grid was used to calculate MCD. Student's t-Test was used to calculate the statistical significance of MCD. MCD in benign ulcers was much higher than in control subjects. MCD in well-differentiated cancers showed MCD higher than control. Poorly-differentiated adenocarcinoma showed lower MCD than well-differentiated adenocarcinoma. It was concluded that the accumulation of mast cells in gastric ulcers is an inflammatory response. MCD is increased in well-differentiated gastric cancers, which may be a mast cell mediated immune response or mast cells may have a role in tumor angiogenesis and produce factors for tumor progression. Poorly-differentiated adenocarcinoma apparently lacks mast cell mediated anti-tumor response in some unexplained way.
الموضوعات
Adult , Biopsy , Cell Count , Endoscopy/methods , Female , Humans , Male , Mast Cells/cytology , Middle Aged , Retrospective Studies , Stomach Neoplasms/immunology , Stomach Ulcer/immunologyالملخص
The study was carried out to evaluate the relationship of inflammatory intestinal cells with the resistance to Trichostrongylus colubriformis infections in three breeds of sheep (Santa Ines, Suffolk and Ile de France), naturally infected. Mast cells, eosinophils, and globule leucocytes were enumerated in intestinal mucosa. Histamine concentration was estimated in intestinal tissue samples and the length of male and female specimens were determined. The three breeds of sheep showed similar cellular response in the small intestine mucosa (P>0.05). There was extensive variation among sheep in the parasitological and inflammatory cell variables, even in lambs of the same breed. In general, animals presenting less inflammatory cells had a larger worm burden, higher fecal egg counts, and larger T. colubriformis worms. The inflammatory cells possibly impaired the parasite's establishment, development, and survival.
Avaliaram-se a associação entre o número de células inflamatórias no intestino delgado e a resistência à infecção por Trichostrongylus colubriformis em ovinos de três raças (Santa Inês, Suffolk e Ile de France), naturalmente infectados. Mastócitos, eosinófilos e leucócitos globulares foram quantificados na mucosa intestinal. A concentração de histamina foi estimada em amostras teciduais do intestino, bem como foi determinado o comprimento de machos e fêmeas de T. colubriformis. A resposta celular foi similar na mucosa intestinal das três raças ovinas (P>0,05). Houve grande variação entre os ovinos em relação aos resultados parasitológicos e celulares, mesmo nos animais de mesma raça. Em geral, os animais que apresentaram número menor de células inflamatórias tiveram cargas parasitárias maiores, contagens de ovos por grama de fezes mais altas e exemplares de T. colubriformis maiores. Os resultados indicaram que mastócitos, eosinófilos e leucócitos globulares prejudicaram o estabelecimento, o desenvolvimento e a sobrevivência dos parasitas.
الموضوعات
Eosinophils/cytology , Leukocytes/cytology , Mast Cells/cytology , Sheep , Trichostrongylus/isolation & purificationالملخص
Posterior cerebellar lesion induced severe focal inflammatory ulcers at the stomach associated with extensive damage of the surface epithelial cells, leading to focal necrotic ulcers. The ulcer index increased maximally and progressively between day 7 and day 14 after lesion. The total mucosal mast cell and degranulated mucosal mast cell increased maximally on day 7 and progressively declined from day 14 to day 21. Gastric histamine content was also significantly increased on day 7 and 14. A significant reduction in mucous content (total CHO:P) was observed within 7-28 days after lesion. The results suggest that the gastric mucosal mast cells play an important role in ulcerogenesis induced by cerebellar lesion.
الموضوعات
Animals , Cell Count , Cerebellum/pathology , Female , Gastric Juice/metabolism , Gastric Mucosa/cytology , Histamine/metabolism , Hydrogen-Ion Concentration , Male , Mast Cells/cytology , Mucus/metabolism , Rats , Rats, Wistar , Stomach Ulcer/metabolismالملخص
Mast cells are known to be effector cells in various inflammatory reactions, but their role in appendicitis is unclear. The present study was undertaken to investigate the extent of mast cell involvement in appendicitis and evaluate their possible role. A total of 150 appendices including normal and inflamed appendices, were assessed for their histological changes and density of neutrophil, lymphocyte and eosinophil infiltration. The mast cells were counted in 1% toluidine blue-stained sections. It was found that eosinophil counts in all the layers were significantly low in normal appendices (P<0.01) and in chronic appendicitis (P<0.1) as compared to acute appendicitis. Mast cell counts were lowest in normal appendices, significantly higher in acute appendicitis (P<0.01) and highest in chronic appendicitis (P<0.001). Obstruction due to faecoliths or parasites were seen in only 20.1% and 2.1% of the inflamed appendices respectively. Hence a Type I hypersensitivity reaction with release of mediators by mast cells might be another triggering factor for the sequence of events leading to appendicitis.
الموضوعات
Acute Disease , Adolescent , Adult , Aged , Aged, 80 and over , Appendicitis/etiology , Appendix/cytology , Child , Child, Preschool , Chronic Disease , Eosinophils/cytology , Female , Humans , Infant , Infant, Newborn , Male , Mast Cells/cytology , Middle Agedالملخص
Birth is the result of complex, well-defined, and coordinated events, that are tightly regulated by endocrine, nervous, and immune responses, and take place primarily in the female reproductive tract. Various mechanisms and mediators involved in pregnancy, labor, and delivery, are highly conserved among different mammalian species and mast cells emerge as potential and crucial participants in these processes, as it is discussed in this review.
الموضوعات
Humans , Female , Pregnancy , Mast Cells/metabolism , Parturition/physiology , Uterus/metabolism , Muscle Contraction/physiology , Corticotropin-Releasing Hormone/metabolism , Gonadal Steroid Hormones/metabolism , Mast Cells/cytology , Muscle, Smooth/physiology , Oxytocin/metabolism , Uterus/cytologyالملخص
For in vitro studies in mesentery, toluidine blue and thionin dyes are generally used. We have tried thionin and acridine orange stains and found it to be good as it showed good colour contrast between mast cells and the background tissue. The two dyes were selected to give good colour contrast.
الموضوعات
Acridine Orange , Animals , Coloring Agents , Male , Mast Cells/cytology , Mesentery/cytology , Phenothiazines , Rats , Rats, Wistar , Staining and Labeling/methodsالملخص
The purpose of this review, based on studies from our laboratory as well as from others, is to summarize salient features of mast cell immunobiology and to describe their associations with gastrointestinal mucosal defense. Gastrointestinal mast cells are involved in many pathologic effects, such as food hypersensitivity. On the other hand, they also play a protective role in defense against parasitic and microbial infections. Thus, they have both positive and negative effects, but presently the mechanisms that control the balance of these various effects are poorly known. It has been suggested that stabilization of mast cells may be a key mechanism to protect the gastrointestinal tract from injury. Few molecules are known to possess both mast cell stabilizing and gastrointestinal cytoprotective activity. These include zinc compounds, sodium cromoglycate, FPL 52694, ketotifen, aloe vera, certain flavonoids such as quercetin, some sulfated proteoglycans such as chondroitin sulfate and dehydroleucodine. Dehydroleucodine, a sesquiterpene lactone isolated from Artemisia douglasiana Besser, exhibits anti-inflammatory and gastrointestinal cytoprotective action. The lactone stimulates mucus production, and inhibits histamine and serotonin release from intestinal mast cells. The lactone could act as a selective mast cell stabilizer by releasing cytoprotective factors and inhibiting pro-inflammatory mast cell mediators.
الموضوعات
Humans , Digestive System , Mast Cells/cytology , Mast Cells/immunology , Anti-Inflammatory Agents , Immunity, Mucosal/immunology , Inflammation/drug therapy , Inflammation/immunology , Inflammation/physiopathology , Lactones/pharmacology , Lactones/therapeutic use , Mast Cells/drug effects , Inflammation Mediators/antagonists & inhibitors , Inflammation Mediators/metabolism , Gastric Mucosa/cytology , Gastric Mucosa/drug effects , Gastric Mucosa/metabolism , Intestinal Mucosa/cytology , Intestinal Mucosa/drug effects , Intestinal Mucosa/immunology , Sesquiterpenes/pharmacology , Sesquiterpenes/therapeutic useالملخص
Los mastocitos (MC) son células del tejido conjuntivo que participan activamente en los mecanismos de comunicación paracrina mediante la liberación de diversos mediadores químicos contenidos en sus gránulos. El presente estudio se efectuó con el propósito de evaluar la distribución de los MC en la glándula mamaria de la perra (Canis familiaris), en periodos activos e inactivo. Las muestras de tejido mamario se obtuvieron a partir de perras adultas. Dichas muestras se procesaron siguiendo el método de inclusión en parafina y los cortes histológicos obtenidos fueron teñidos con azul de tolouidina para posteriormente efectuar la cuantificación de MC por mm², considerando para este fin el estroma interalveolar y el estroma interlobulillar del tejido mamario. Durante el periodo activo de la glándula mamaria, la población de MC presentes en el estroma disminuye significativamente respecto del periodo inactivo (P< 0.05). Estos resultados en conjunto sugieren que los MC presentes en el estroma de la glándula mamaria de perra, participan activamente en los cambios proliferativos que experimentan el tejido conjuntivo laxo areolar, dependiendo del estadio funcional de la glándula
الموضوعات
Animals , Female , Dogs/anatomy & histology , Mammary Glands, Animal/cytology , Mast Cells/cytology , Stromal Cells , Dogs/physiologyالملخص
Mast cell dynamics has been studied in relation to cystogenesis of ovarian follicles in the house rat. Immature rats were injected (s.c.) daily with DHEA (6.0 mg/100 g body weight) and were sacrificed on the day 8, 16 and 24 of the start of treatment. Ovarian sections of the treated rats had majority of the antral follicles undergoing atresia or in early stages of cystogenesis. Completely developed cysts were evident from the ovarian surface after 24 days of daily treatment. Treatment for 8 days resulted in significant increase in the number of alcian blue-positive ovarian mast cells. Ovaries after 16 days of DHEA treatment showed no marked change with regard to the number of total mast cells per unit area and staining characteristics. However, a significant rise in ovarian mast cell counts was recorded after 24 days of treatment and most of the cells contained safranin-positive red granules. This increase was attributed due to the increase in their number in medulla and stroma around the cystic follicles.