Bacteriological and pathological investigations on the preputial glands of one-year-old C57BL/6NCrl mice maintained in individually ventilated cages

Spontaneous infections of the preputial glands represent overlooked health problems in mice that could raise welfare concerns and potentially confound scientific experiments. Agents involved in preputial gland infections have rarely been investigated, with opportunistic pathogens of laboratory animals usually detected in inflamed preputial glands. The aim of this study was to investigate the prevalence of bacterial infection in the preputial glands and the relationship between haematological and pathological changes and infection status. We analysed 40 preputial glands from 20 one-year-old C57BL/6NCrl male mice by using bacteriology, haematology and pathology. Bacteria were isolated from 16/20 (80%) mice, for a total of 32/40 (80%) examined preputial glands. Enterobacter cloacae, Pasteurella spp., Klebsiella spp. and Staphylococcus aureus were identified in 35%, 17.5%, 15% and 12.5% of the examined glands, respectively. Preputial gland inflammation was identified in 29/40 (72.5%) glands and was classified as chronic interstitial adenitis in 27 cases and suppurative adenitis in the remaining two glands. No haematological changes were found in mice with infected glands. Histologically, the presence of intralesional bacteria, intraluminal necrotic material, intraluminal keratin accumulation, interstitial inflammatory cell infiltrate and granulocytes (intraluminal and/or interstitial), along with total inflammatory score and total histopathological score, were significantly increased in infected glands and correlated with the bacterial load. Most severe inflammatory changes were identified after S. aureus infection, while ductal hyperkeratosis was significantly increased in glands infected with Klebsiella spp. In conclusion, preputial gland infection was a common event in one-year-old C57BL/6NCrl mice, and bacterial load correlated with pathological findings, while systemic effects were not highlighted by haematology.

Transcriptional Differences in Lipid-Metabolizing Enzymes in Murine Sebocytes Derived from Sebaceous Glands of the Skin and Preputial Glands

Sebaceous glands are adnexal structures, which critically contribute to skin homeostasis and the establishment of a functional epidermal barrier. Sebocytes, the main cell population found within the sebaceous glands, are highly specialized lipid-producing cells. Sebaceous gland-resembling tissue structures are also found in male rodents in the form of preputial glands. Similar to sebaceous glands, they are composed of lipid-specialized sebocytes. Due to a lack of adequate organ culture models for skin sebaceous glands and the fact that preputial glands are much larger and easier to handle, previous studies used preputial glands as a model for skin sebaceous glands. Here, we compared both types of sebocytes, using a single-cell RNA sequencing approach, to unravel potential similarities and differences between the two sebocyte populations. In spite of common gene expression patterns due to general lipid-producing properties, we found significant differences in the expression levels of genes encoding enzymes involved in the biogenesis of specialized lipid classes. Specifically, genes critically involved in the mevalonate pathway, including squalene synthase, as well as the sphingolipid salvage pathway, such as ceramide synthase, (acid) sphingomyelinase or acid and alkaline ceramidases, were significantly less expressed by preputial gland sebocytes. Together, our data revealed tissue-specific sebocyte populations, indicating major developmental, functional as well as biosynthetic differences between both glands. The use of preputial glands as a surrogate model to study skin sebaceous glands is therefore limited, and major differences between both glands need to be carefully considered before planning an experiment.

Transcriptional differences of lipid-metabolizing enzymes in sebocytes derived from sebaceous glands of the skin and pre-putial glands

Sebaceous glands are adnexal structures, which critically contribute to skin homeostasis and the establishment of a functional epidermal barrier. Sebocytes, the main cell population found within the sebaceous glands, are highly specialized lipid-producing cells. Sebaceous gland-resembling tissue structures are also found in male rodents in form of preputial glands. Similar to sebaceous glands, they are composed of lipid-specialized sebocytes. Due to a lack of adequate organ culture models for skin sebaceous glands and the fact that preputial glands are much larger and easier to handle, previous studies have used preputial glands as a model for skin sebaceous glands. Here, we compared both types of sebocytes, using a single cell RNA sequencing approach, to unravel potential similarities and differences between the two sebocyte populations. In spite of common gene expression patterns due to general lipid-producing properties, we found significant dif-ferences in the expression levels of genes encoding enzymes involved in the biogenesis of spe-cialized lipid classes. Specifically, genes critically involved in the mevalonate pathway, including squalene synthase, as well as the sphingolipid salvage pathway, such as ceramide synthase, (acid) sphingomyelinase or acid and alkaline ceramidases, were significantly less expressed by preputial gland sebocytes. Together, our data revealed tissue-specific sebocyte populations, indicating major developmental, functional as well as biosynthetic differences between both glands. The use of preputial glands as surrogate model to study skin sebaceous glands is therefore limited, and major differences between both glands need to be carefully considered before planning an ex-periment.

Histomorphological perspectives of preputial and clitoral glands of soft-furred field rat Millardia meltada

The present study was an attempt to understand the sexual dimor-phism of the integumentary scent glands of soft-furred field rat Millardia meltada from the perspectives of anatomy, morphology and histology with view to correlate with the sex-specific pheromones they produce. The scent gland of male is known as preputial gland, and female, the clitoral gland. The rats, that are agricultural pests were field caught, the glands of males and females of almost identical size were dissected out, and subjected to gravimetric, morphometric and histological analyses. Both glands are yellowish-brown, pear-shaped, and dorsoventrally compressed. The mean weight, length and width of preputial glands are significantly (p < 0.05) larger than that of the clitoral glands. The preputial gland is composed of sebaceous glandular lobules and apocrine glandular lobules whereas the clitoral gland is formed only of sebaceous glandular lobules. The sebaceous glandular lobules of both preputial and clitoral glands are filled with a wax-like material. Thus, the scent glands of the soft-furred male field rats exhibit sexual dimorphism in respect histoarchitecture of the glands and the nature of the secretory material. This sexual dimorphism of the scent glands may reflect control by male and female sex hormones impinging on specific roles as sex attractant pheromones.

Anatomy and Physiology of Animal Model Rats in Biomedical Research

A distinguishing feature of rodents, including rats, is the absence of canines and thepresence of prominent incisors. Rats are monophydontic, meaning they grow one setof teeth in their lifetime. The enamel of the rodent incisor contains iron, which givesit its yellow-orange color. Rats are mammals and as such, possess many similaritieswith other mammals. Only the peculiarities of the rat’s anatomy are addressed. Malerats reach puberty at 40 - 60 days of age. Descent of the testes usually occursbetween days 30 - 60. Sperm counts vary by strain. The male rat has an os penis.Male rats have the following accessory sexual organs: ampulla, seminal vesicles,prostate, bulbourethral glands, coagulating glands, and preputial glands. Thecoagulating gland and prostatic and vesicular secretions are responsible for thecopulation plug, a firm plug deposited in the vagina of the female after copulation.(This plug, when found outside the female rat, is capsuleshaped and approximately5 mm long.) The male rat has no nipples. The adult male rat has a prominentscrotum and a longer anogenital distance than the female rat.

Blattes de Byzance in India: Mollusk Opercula and the History of Perfumery

Aromatics derived from animals have played a very important role in the history of perfumery. The most well-known of these materials are musk from the preputial glands of the musk deer, ambergris produced in the stomach of the sperm whale, and civet from the anal glands of the civet cat. Two other notable materials are castoreum from the beaver, and hyraceum from the solidified urine of the African hyrax. The material that I will call ‘sweet hoof’ in this article, also called blattes de Byzance and unguis odoratus, is another fragrant material derived from an animal, consisting of the opercula of certain marine snails. With its marine origins ‘sweet hoof’ is intrinsically linked to the ocean and to trade, and it has also long been of importance all the way from the Mediterranean to China and Japan. Indeed, it is probably the most ancient animal derived aromatic to have an extensive global use, being mentioned in ancient Babylonian incense recipes. Yet, quite probably owing to its very low profile in more commonly studied genres of Sanskrit texts, the South Asian chapter of the history of ‘sweet hoof’ has yet to be written.

Detection of α2u-globulin in rat pup preputial gland by MALDI-TOF mass spectrometry

The α2u-globulin, a soluble protein identified in the urine and preputial gland of adult male rat is reported to be pheromone carrier. The pup preputial gland plays a significant role in chemical communication for mother-young interaction; however, the presence of a pheromone-carrying protein in the pup preputial gland has not been confirmed. Therefore, the present study was carried out to identify the α2u-globulin in the pup preputial gland by Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF). The preputial glands of prepubertal rats were subjected to one-dimensional SDS-PAGE. In-gel trypsin digestion of a 18 kDa band was carried out and analyzed by MALDI-TOF. The results of a MASCOT search showed the presence of α2u-globulin in the 18 kDa band. In contrast to the report of the synthesis of this protein only in adult rats, the identification of this protein in pup preputial gland is significant. The results suggest that synthesis of α2u-globulin in the rat preputial gland starts in the prepubertal stage itself. In prepubertal rats, the preputial gland is a source of pheromone for performing anogenital licking behaviour by the mother rat. Since α2u-globulin belongs to the lipocalin (ligand carrier) family, it might carry the volatile for processing pheromonal communication in mother-pup bonding in rat.