E2F-1-deficient NOD/SCID mice developed showing decreased saliva production

Persistent colonization of Candida albicans yeast on the tongue in NOD/SCID.e2f1-/- mice

Candida albicans is a commensal fungus that commonly colonizes as opportunistic pathogens human mucosal surfaces. Our aim was to observe persistent infection of C. albicans on the tongue in NOD/SCID.e2f1(-/-) mice, which naturally was decreased saliva and undeveloped T and B cells. Using a cotton swab, a C. albicans suspension was applied to the tongue of wild type and mutant mice after disinfection using 0.2% Chlorhexidine (CHX). In our earlier report, it was found that many times inoculation per day and consecutive day inoculations without disinfection of indigenous microorganisms did not induce significant C. albicans infection for 48 h in the oral cavity. In this study, using inoculation of four sets {one inoculation after disinfection by CHX + interval (3 or 4 d)} induced longer term and higher numbers infection for 4 days on the tongue than results in a previous report in both NOD/SCID.e2f1(+/+) and NOD/SCID.e2f1(-/-) mice. Repeat of disinfection to indigenous microorganisms and inoculation with interval established and realized a new model for persistent infection of C. albicans yeast. However, decreased saliva and consecutive inoculations per day did not contribute to the persistent colonization on the tongue in the mice. It is suggested that the interaction between C. albicans and indigenous microorganisms is important for persistent colonization of C. albicans yeast on the tongue rather than decreased saliva in the oral cavity.

E2f1-deficient NOD/SCID mice have dry mouth due to a change of acinar/duct structure and the down-regulation of AQP5 in the salivary gland

Non-obese diabetic (NOD) mice have been used as a model for dry mouth. NOD mice lacking the gene encoding E2f1, a transcription factor, develop hyposalivation more rapidly progressively than control NOD mice. However, the model mice are associated with an underlying disease such as diabetes. We have now established E2f1-deficient NOD/severe combined immunodeficiency disease (NOD/SCID.E2f1(-/-)) mice to avoid the development of diabetes (Matsui-Inohara et al., Exp Biol Med (Maywood) 234(12):1525-1536, 2009). In this study, we investigated the pathophysiological features of dry mouth using NOD/SCID.E2f1(-/-) mice. In NOD/SCID.E2f1(-/-) mice, the volume of secreted saliva stimulated with pilocarpine is about one third that of control NOD/SCID mice. In behavioral analysis, NOD/SCID.E2f1(-/-) mice drank plenty of water when they ate dry food, and the frequency and time of water intake were almost double compared with control NOD/SCID mice. Histological analysis of submandibular glands with hematoxylin-eosin stain revealed that NOD/SCID.E2f1(-/-) mice have more ducts than NOD/SCID mice. In western blot analysis, the expression of aquaporin 5 (AQP5), a marker of acinar cells, in parotid and in submandibular glands of NOD/SCID.E2f1(-/-) mice was lower than in NOD/SCID mice. Immunohistochemical analysis of parotid and submandibular acini revealed that the localization of AQP5 in NOD/SCID.E2f1(-/-) mice differs from that in NOD/SCID mice; AQP5 was leaky and diffusively localized from the apical membrane to the cytosol in NOD/SCID.E2f1(-/-) mice. The ubiquitination of AQP5 was detected in submandibular glands of NOD/SCID.E2f1(-/-) mice. These findings suggest that the change of acinar/duct structure and the down-regulation of AQP5 in the salivary gland cause the pathogenesis of hyposalivation in NOD/SCID.E2f1(-/-) mice.

Effects of salivary protein flow and indigenous microorganisms on initial colonization of Candida albicans in an in vivo model

BACKGROUND

Candida albicans is a dimorphic fungus that is part of the commensal microbial flora of the oral cavity. When the host immune defenses are impaired or when the normal microbial flora is disturbed, C. albicans triggers recurrent infections of the oral mucosa and tongue. Recently, we produced NOD/SCID.e2f1-/- mice that show hyposalivation, decrease of salivary protein flow, lack IgA and IgG in saliva, and have decreased NK cells. Our objective was to characterize C. albicans infection and biofilm formation in mice.

METHODS

NOD/SCID.e2f1-/- mice were used as an animal model for C. albicans infection. C. albicans yeast and hyphal forms solutions were introduced in the oral cavity after disinfection by Chlorhexidine.

RESULTS

The numbers of C. albicans colonized and decreased in a time-dependent manner in NOD/SCID.e2f1+/+ after inoculation. However, the colonization levels were higher in NOD/SCID.e2f1+/+ than NOD/SCID.e2f1-/- mice. In the mice fed 1% sucrose water before inoculation, C. albicans sample was highly contaminated by indigenous microorganisms in the oral cavity; and was not in the mice fed no sucrose water. The colonization of C. albicans was not influenced by the contamination of indigenous microorganisms. The hyphal form of C. albicans restricted the restoration of indigenous microorganisms. The decreased saliva in NOD/SCID.e2f1-/- did not increase the colonization of C. albicans in comparison to NOD/SCID.e2f1+/+ mice. We suggest that the receptor in saliva to C. albicans may not be sufficiently provided in the oral cavity of NOD/SCID.e2f1-/- mice.

CONCLUSION

The saliva protein flow may be very important for C. albicans initial colonization, where the indigenous microorganisms do not affect colonization in the oral cavity.

Animal models as tools to investigate antidiabetic and anti-inflammatory plants

Plants have been historically used for diabetes treatment and related anti-inflammatory activity throughout the world; few of them have been validated by scientific criteria. Recently, a large diversity of animal models has been developed for better understanding the pathogenesis of diabetes mellitus and its underlying inflammatory mechanism and new drugs have been introduced in the market to treat this disease. The aim of this work is to review the available animal models of diabetes and anti-inflammatory activity along with some in vitro models which have been used as tools to investigate the mechanism of action of drugs with potential antidiabetic properties and related anti-inflammatory mechanism. At present, the rigorous procedures for evaluation of conventional antidiabetic medicines have rarely been applied to test raw plant materials used as traditional treatments for diabetes; and natural products, mainly derived from plants, have been tested in chemically induced diabetes model. This paper contributes to design new strategies for the development of novel antidiabetic drugs and its related inflammatory activity in order to treat this serious condition which represents a global public health problem.

Impact of oral health in patients with multiple sclerosis and epilepsy: a survey in a neurology clinic

This study investigated the impact of oral health on neurological disorders using the Oral Health Impact Profile (OHIP). A total of 460 subjects completed the OHIP, including 141 control subjects who did not have any neurological conditions. Of the 319 subjects with a neurological diagnosis who were enrolled in the study, 31% had multiple sclerosis (MS), 34% had epilepsy, and 34% had other neurological conditions. Compared to the control group, mean age (p = .001), education (p = .003), and household income levels (p ≤ .001) were statistically significantly lower among subjects with epilepsy than in the other two groups. The majority of the study populations were Caucasian and the percentage was highest in those with MS (87%). Patients with any neurologic diagnosis had greater physical pain and disability than controls. Adjusting for demographic variables, the impact of physical disability was statistically significantly higher in patients with any neurological diagnosis (including MS and epilepsy) (OR = 4.49). In multinomial regression, the strongest association of physical disability impact was noted in patients with epilepsy (OR = 5.17). The physical disability domain of the OHIP is more commonly associated with a neurological diagnosis, including MS, and the association is strongest in patients with diagnosis of epilepsy.

Roles of salivary components in Streptococcus mutans colonization in a new animal model using NOD/SCID.e2f1-/- mice

Streptococcus mutans plays an important role in biofilm formation on the tooth surface and is the primary causative agent of dental caries. The binding of S. mutans to the salivary pellicle is of considerable etiologic significance and is important in biofilm development. Recently, we produced NOD/SCID.e2f1(-/-) mice that show hyposalivation, lower salivary antibody, and an extended life span compared to the parent strain: NOD.e2f1(-/-). In this study we used NOD/SCID.e2f1(-/-) 4 or 6 mice to determine the roles of several salivary components in S. mutans colonization in vivo. S. mutans colonization in NOD/SCID.e2f1(-/-) mice was significantly increased when mice were pre-treated with human saliva or commercial salivary components. Interestingly, pre-treatment with secretory IgA (sIgA) at physiological concentrations promoted significant colonization of S. mutans compared with sIgA at higher concentrations, or with human saliva or other components. Our data suggest the principal effects of specific sIgA on S. mutans occur during S. mutans colonization, where the appropriate concentration of specific sIgA may serve as an anti-microbial agent, agglutinin, or an adherence receptor to surface antigens. Further, specific sIgA supported biofilm formation when the mice were supplied 1% sucrose water and a non-sucrose diet. The data suggests that there are multiple effects exerted by sIgA in S. mutans colonization, with synergistic effects evident under the condition of sIgA and limited nutrients on colonization in NOD/SCID.e2f1(-/-) mice. This is a new animal model that can be used to assess prevention methods for dental biofilm-dependent diseases such as dental caries.

Sjögren's syndrome: studying the disease in mice

Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by inflammation of exocrine tissues accompanied by a significant loss of their secretory function. Clinical symptoms develop late and there are no diagnostic tests enabling early diagnosis of SS. Thus, particularly to study these covert stages, researchers turn to studying animal models where mice provide great freedom for genetic manipulation and testing the effect of experimental intervention. The present review summarizes current literature pertaining to both spontaneous and extrinsic-factor induced SS-like diseases in mouse models, discussing advantages and disadvantages related to the use of murine models in SS research.

E2F1-deficient NOD/SCID mice are an experimental model for dry mouth

Saliva contains a wide variety of secretory proteins, including alpha-amylase, lysozyme, peroxidase, immunoglobulins, and mucins. Hyposecretion of saliva and consequent dry mouth will lead to severe dental caries, periodontal disease, and mucosal infections, resulting in degrade of quality of life. Polyposia development is one of sign usually seen in dry mouth patients. However, little is reported in dry mouth-model animal regarding the entire process of polyposia development. We investigated the behavior of polyposia in E2F1-deficient non-obese diabetic/severe combined immunodeficiency disease (NOD/SCID) mice, as a dry mouth-model. E2F1-deficient NOD/SCID mice secreted small amount of saliva under the stimulation with a cholinergic agonist, pilocarpine, compared with control mice. The frequency of water intake by E2F-1-deficient NOD/SCID mice was more than that by control mice. These results suggest that E2F-1-deficient NOD/SCID mice show a behavior similar to polyposia and are very useful experimental model of dry mouth patients.