Cellular expression of Bcl-2 and Bax in atrophic submandibular glands of rats

Duct ligation/de-ligation model: exploring mechanisms for salivary gland injury and regeneration

Sialadenitis and sialadenitis-induced sialopathy are typically caused by obstruction of the salivary gland ducts. Atrophy of the salivary glands in experimental animals caused by duct ligation exhibits a histopathology similar to that of salivary gland sialadenitis. Therefore, a variety of duct ligation/de-ligation models have been commonly employed to study salivary gland injury and regeneration. Duct ligation is mainly characterised by apoptosis and activation of different signaling pathways in parenchymal cells, which eventually leads to gland atrophy and progressive dysfunction. By contrast, duct de-ligation can initiate the recovery of gland structure and function by regenerating the secretory tissue. This review summarizes the animal duct ligation/de-ligation models that have been used for the examination of pathological fundamentals in salivary disorders, in order to unravel the pathological changes and underlying mechanisms involved in salivary gland injury and regeneration. These experimental models have contributed to developing effective and curative strategies for gland dysfunction and providing plausible solutions for overcoming salivary disorders.

Short-Chain Fatty Acids Alleviate Hepatocyte Apoptosis Induced by Gut-Derived Protein-Bound Uremic Toxins

Chronic kidney disease (CKD) is characterized with the influx of uremic toxins, which impairs the gut microbiome by decreasing beneficial bacteria that produce short-chain fatty acids (SCFAs) and increasing harmful bacteria that produce gut-derived protein-bound uremic toxins (PBUTs). This study aimed to assess the proapoptotic effects of three major gut-derived PBUTs in hepatocytes, and the effects of SCFAs on apoptosis phenotype in vitro. HepG2 (human liver carcinoma cells) and THLE-2 (immortalized human normal liver cells) cell line were incubated with 0, 2, 20, 200, 2000 μM p-cresol sulfate (PCS), indoxyl sulfate (IS), and hippuric acid (HA), respectively, for 24 h. Flow cytometry analysis indicated that three uremic toxins induced varying degrees of apoptosis in hepatocytes and HA represented the highest efficacy. These phenotypes were further confirmed by western blot of apoptosis protein expression [Caspase-3, Caspase-9, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax)]. Human normal hepatocytes (THLE-2) are more sensitive to PBUTs-induced apoptosis compared with human hepatoma cells (HepG2). Mechanistically, extracellular HA could enter hepatocytes, increase reactive oxygen species (ROS) generation, and decrease mitochondrial membrane potential dose-dependently in THLE-2 cells. Notably, coculture with SCFAs (acetate, propionate, butyrate) for 24 h significantly improved HA-induced apoptosis in THLE-2 cells, and propionate (500 μM) represented the highest efficacy. Propionate reduction of apoptosis was associated with improving mitochondria dysfunction and oxidative stress in a manner involving reducing Caspase-3 expression, ROS production, and increasing the Bcl-2/Bax level. As such, our studies validated PBUTs accumulation might be an important cause of liver dysfunction in patients with CKD, and supplementation of SCFAs might be a viable way to protect the liver for patients with CKD.

Toxicity of 2-methyl-4-chlorophenoxy acetic acid alone and in combination with cyhalofop-butyl to Cyprinus carpio embryos

Herbicides may pose considerable danger to non-target aquatic organisms and further threaten human health. The present investigation was aimed to assess the effects of 2-methyl-4-chlorophenoxy acetic acid (MCPA-Na) on Cyprinus carpio embryos. Embryos were exposed to six concentrations of MCPA-Na (0, 52, 54, 56, 58 and 60 mg/L) for 96 h. A series of symptoms were observed in developmental embryos during MCPA-Na exposure, including increased death, hatching inhibited and morphological deformities. Further, MCPA-Na exposure leading to a series of morphological changes (pericardial edema, tail deformation, and spine deformation) in embryos, which were consistent with modifications in the associated genes. In this work, we also investigated the joint toxicity of herbicides (MCPA-Na and cyhalofop-butyl) commonly used in paddy fields on carp embryos, using the 96 h-LC₅₀ of herbicides (59.784 mg/L MCPA-Na and 1.472 mg/L cyhalofop-butyl) and confirmed that a synergistic effect existing in the binary mixtures.

Experimental Animal Model Systems for Understanding Salivary Secretory Disorders

Salivary secretory disorders are life-disrupting pathologic conditions with a high prevalence, especially in the geriatric population. Both patients and clinicians frequently feel helpless and get frustrated by the currently available therapeutic strategies, which consist mainly of palliative managements. Accordingly, to unravel the underlying mechanisms and to develop effective and curative strategies, several animal models have been developed and introduced. Experimental findings from these models have contributed to answer biological and biomedical questions. This review aims to provide various methodological considerations used for the examination of pathological fundamentals in salivary disorders using animal models and to summarize the obtained findings. The information provided in this review could provide plausible solutions for overcoming salivary disorders and also suggest purpose-specific experimental animal systems.

Identification of drug targets and potential molecular mechanisms for Wantong Jingu Tablet extract in treatment of rheumatoid arthritis: bioinformatics analysis of fibroblast-like synoviocytes

Background

Rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLSs) play important roles in pathogenesis of rheumatoid arthritis (RA). Wantong Jingu Tablet (WJT), a mixture of traditional Chinese medicine, is a potentially effective therapy for RA, but its underlying mechanism is unclear. In this study, we explore the effects of WJT on human RA-FLSs and the underlying molecular mechanism.

Methods

The major components of WJT were determined using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS). Cell proliferative ability was evaluated by CCK-8, colony formation assay, and EdU incorporation assay. Cell apoptotic capacity was examined by caspase-3 and caspase-9 activity test. Protein levels of Bax and Bcl-2 were investigated by western blotting. High-throughput sequencing and bioinformatics analysis were conducted to screen and identify targeted genes, followed by identification by qRT-PCR and western blotting.

Results

In this study, we have identified 346 compounds in WJT. Our results showed that WJT inhibited the RA-FLSs proliferation, and promoted apoptosis in a dose- and time-dependent manner. More importantly, 184 differentially expressed genes (DEGs) has been screened after WJT treatment based on DEGSeq2 and 278 DEGs was identified by DEGSeq2 combined with WGCNA. Then, 10 hub genes were identified based on two different analyses, while the expression levels of only SMC3, THOC1, BUB1, and STAG2 were decreased after WJT treatment, which was identical to the sequencing profiles.

Conclusions

WJT exerted its anti-proliferation and pro-apoptosis effects possibly through suppressing the expression of SMC3, THOC1, BUB1, and STAG2 in RA-FLSs. Thus, therapeutics targeting these genes may be a promising strategy for rescuing RA.

Postnatal changes in the development of rat submandibular glands in offspring of diabetic mothers: Biochemical, histological and ultrastructural study

Development and maturation of submandibular salivary glands are influenced by intrauterine diabetic environment. Several studies investigated the effects of diabetes on the salivary glands. However, the effects of maternal diabetes on the submandibular glands of the offspring was not properly examined. Therefore, the present study was designed to describe the changes in the development of the submandibular glands of the offspring of diabetic mothers. The submandibular glands of the offspring of Streptozotocin (STZ)-induced diabetic female rats were examined at two and four weeks after birth. Detection of mRNA demonstrated that maternal diabetes affects the level of different indicators. The reduction of expression of epidermal growth factor (EGF); a protein mitogen, cytokeratin 5 (CK5); an epithelial cell progenitor, CK7 and aquaporin 5 (AQP5); differentiation markers and B cell lymphoma 2 (Bcl2); an antiapoptotic marker were found. Increase in Bcl2-associated X protein (Bax); an apoptotic marker was detected. These changes indicate their effects on saliva secretion, glands tumorigenesis, growth of normal oral flora and oral microbes, with decreased protein synthesis and production of xerostomia and dental caries. Loss of normal glandular architecture, significant increase in fibrosis, by the detection of collagen fibers, and stagnation of secretory granules were found with atrophic changes in the acinar cells. Marked defect of polysaccharides in the acinar cells, denoting functional changes, was manifested by significant reduction of the intensity of periodic acid-Schiff (PAS) reaction. The positive immunoreactivity of caspase-3, denoting cellular apoptosis, and minimal reaction of alpha-smooth muscle actin (α SMA) and proliferating cell nuclear antigen (PCNA) were evident in the offspring of diabetic mothers. We conclude that maternal diabetes produces degenerative effects in the structure and function of the submandibular salivary glands of the offspring, reflecting possible influences on their secretory activity affecting oral and digestive health.

[Changes of myoepithelial cells during regeneration of parotid gland]

OBJECTIVE

To investigate the changes on the number and distribution of myoepithelial cells (MECs) during parotid gland regeneration.

METHODS

A total of 54 Wistar rats were divided into eight experimental groups and one normal control group, with six rats in each group. The right parotid ducts of the rats in the experimental groups were ligated for 14 days and then reopened. The parotid tissue specimens were harvested at days 0, 1, 3, 5, 7, 10, 14, and 21. The histological changes of the regenerating gland were examined using hematoxylin-eosin staining. Immunohistochemical labeling was also performed to investigate the changes in the number and distribution of MECs at different time points of parotid regeneration. Both the histological and immunohistochemical changes observed in the experimental groups were compared with those in the normal control group.

RESULTS

The parotid gland showed marked atrophy 14 days after ligation. Most acinar cells disap- peared, but the number of duct-like structures obviously increased. MECs apparently increased in number and were mainly located at the periphery of the duct-like structures. Three days after duct reopening, the number of acinar cells significantly increased and the duct-like structures significantly reduced. Meanwhile, MECs also decreased in number and were mainly located at the periphery of the newly formed acini and duct-like structures. The number of MECs noticeably decreased 3 and 5 days after duct reopening. At 14 days after duct reopening, the glandular structures and the number and distribution of MECs returned to normal compared with those in the normal control group.

CONCLUSION

The number and distribution of MECs returned to normal condition after parotid gland atrophy. Parotid regeneration mainly occurred within 5 days after duct reopening.

[Changes of myoepithelial cells during regeneration of parotid gland]

OBJECTIVE

To investigate the changes on the number and distribution of myoepithelial cells (MECs) during parotid gland regeneration.

METHODS

A total of 54 Wistar rats were divided into eight experimental groups and one normal control group, with six rats in each group. The right parotid ducts of the rats in the experimental groups were ligated for 14 days and then reopened. The parotid tissue specimens were harvested at days 0, 1, 3, 5, 7, 10, 14, and 21. The histological changes of the regenerating gland were examined using hematoxylin-eosin staining. Immunohistochemical labeling was also performed to investigate the changes in the number and distribution of MECs at different time points of parotid regeneration. Both the histological and immunohistochemical changes observed in the experimental groups were compared with those in the normal control group.

RESULTS

The parotid gland showed marked atrophy 14 days after ligation. Most acinar cells disap- peared, but the number of duct-like structures obviously increased. MECs apparently increased in number and were mainly located at the periphery of the duct-like structures. Three days after duct reopening, the number of acinar cells significantly increased and the duct-like structures significantly reduced. Meanwhile, MECs also decreased in number and were mainly located at the periphery of the newly formed acini and duct-like structures. The number of MECs noticeably decreased 3 and 5 days after duct reopening. At 14 days after duct reopening, the glandular structures and the number and distribution of MECs returned to normal compared with those in the normal control group.

CONCLUSION

The number and distribution of MECs returned to normal condition after parotid gland atrophy. Parotid regeneration mainly occurred within 5 days after duct reopening.