Universidade Federal Do Para

Stress occurs as a reaction to mental and emotional pressure, anxiety, or scarring. Chronic stress is defined as constant submission to these moments. It can affect several body systems, increase blood pressure, and weaken immunity, thereby interfering with physiological health processes. Thus, this study aims to evaluate the effects of chronic stress on the redox status and histomorphological parameters of salivary glands. Thirty-two albino Wistar male rats were randomly divided into two groups: chronic stress and control. Chronically stressed animals were subjected to a restraint protocol by introducing them into a polyvinyl tube for 4 hours daily for 28 days, allowing immobilization of their movements. Subsequently, the animals were euthanized for further collection of the parotid and submandibular salivary glands. The redox state of the glands was evaluated using the antioxidant capacity against peroxyl radicals (ACAP) and thiobarbituric acid reactive substances (TBARS) assays. Histological analysis was performed through morphometry of the tissues stained with hematoxylin and eosin and histochemical through picrosirius red staining. Both the parotid and submandibular glands of stressed rats exhibited oxidative stress due to a decrease in ACAP and an increase in TBARS levels. However, the parotid glands are more susceptible to harmful changes in the tissue, such as an increase in the stromal area and in the collagen area fraction, decrease in the acinar area, and smaller size of the acinus and ducts. Our results suggest that chronic stress may cause harmful modulation of the redox state of the salivary glands, with different histological repercussions.

This study investigated the effects of prenatal exposure to pequi oil and 17α-ethinylestradiol (EE2) on the histomorphometry and receptor expression (androgen receptor (AR) and estrogen receptor alpha (ERα) in gerbil ovaries (Meriones unguiculatus) during aging. Experimental groups included: control, vehicle (mineral oil), EE2: 15 µg/kg/day from gestational days 18-22, EE2/Pe: EE2 from days 18-22 and 300 mg/kg of pequi oil from days 18-26, and Pe: pequi oil only, via gavage. Female offspring were euthanized at 12 months, and ovaries were collected, processed histologically, and sectioned. Histological sections were stained with hematoxylin-eosin to analyze the superficial epithelium height and the tunica albuginea thickness. Immunohistochemistry for AR and ERα was performed, and the percentage of positive nuclei for these receptors was quantified in the theca interna, granulosa cells within follicles, and the interstitial gland. Data were analyzed using analysis of variance (ANOVA), Tukey's, and Kruskal-Wallis tests. The data revealed a significant decrease (p < 0.05) in the thickness of the tunica albuginea in the EE2 group, whereas this thickness was increased in the EE2/Pe and Pe groups. Epithelial height was lower in the EE2 group and higher in the EE2/Pe group. No significant changes in AR immunoreactivity were observed. In multilaminar follicles, ERα immunostaining was elevated in granulosa cells in the Pe group and in theca cells of the EE2 group. Additionally, the interstitial gland in the Pe group showed an increase in ERα expression. Pequi oil exposure upregulated ERα more markedly than AR during folliculogenesis and in interstitial cells, suggesting endocrine-modulating potential and relevance for ovarian regulation during aging.

The genus Myxobolus, belonging to the class Myxozoa, is a cnidarian genus characterized by ellipsoidal or rounded myxospores with two polar capsules located in the anterior sutural plane, commonly without caudal projections. However, diverse morphologies have been described in recent studies of myxospores, exhibiting various appendage forms. The present study describes the morphological and molecular characteristics of a new species of Myxobolus in the red piranha Pygocentrus nattereri. In 16 % (3/18) of the fish specimens captured in Lake Sacaizal, Amapá State, whitish cysts containing ovoid myxospores with dendritic caudal appendages were observed in the anterior chamber of the eye. The myxospores measured 17.7 μm long, 15.6 μm wide, and 14.0 μm thick and had two equally sized pyriform polar capsules 9.9 μm long and 4.2 μm wide. Phylogenetic analyses showed that the newly identified species, Myxobolus medusae n. sp., formed a clade with other species of Myxobolus without appendages and Henneguya, which infects Characiformes in Brazil, with a genetic distance above 12 %. These morphological and molecular data provide insights into a new species of the genus Myxobolus in P. nattereri, a fish species of socioeconomic importance in the Amazon region.