Antihyperalgesic and antiallodynic effect of sirolimus in rat model of adjuvant arthritis

A STUDY OF THE INFLUENCE OF JUVENILE ADJUVANT ARTHRITIS ON DENTAL HARD TISSUES CONDITION IN EXPERIMENTAL ANIMALS

OBJECTIVE

The aim: To study the intensity and depth of carious tooth lesions in rats with experimental juvenile adjuvant-induced arthritis.

PATIENTS AND METHODS

Materials and methods: An experimental study on a model of juvenile adjuvant arthritis (JAA) in 10 one-month-old rats induced by method of A.M. Bendele was carried out. 10 rats of the same age were intact. Injection of adjutant in rats of experimental group led to the development of acute local reaction and then caused generalized joint reaction of autoimmune origin. The performed basic therapy of JAA promoted transition of acute autoimmune process to chronic. Rats were withdrawn from the experiment in 58 days and the dental-jaw blocks were made, in which the intensity and depth of carious lesions of the masticatory group of teeth were determined.

RESULTS

Results: The course of JAA was accompanied by the development of dental caries in 100% of experimental animals. It was found that the intensity of carious teeth lesions in terms of the number of carious teeth and cavities is probably higher than in intact rats (respectively 4.3 ± 0.3 vs. 2.2 ± 0.6 and 4.5 ± 0.3 vs. 2.3 ± 0.7, p <0.001). In rats with JAA, mostly middle and deep carious cavities were revealed, at the same time in intact rats - superficial and middle carious cavities were observed.

CONCLUSION

Conclusions: It has been established that adjuvant arthritis is accompanied by 100% prevalence of dental caries, high intensity of carious process, presence of middle and deep carious cavities, that confirm the negative influence of autoimmune disease on the condition of the hard tooth tissues.

THE POTENCY OF ALPHA LIPOIC ACID AS ANTI INFLAMMATORY ON THE COMPLETE FREUND'S ADJUVANT-INDUCED RHEUMATOID ARTHRITIS IN RAT MODEL

Rheumatoid arthritis (RA) is an autoimmune diseases which is characterized by chronic inflammation of the synovial tissue in joints. This research was designed to investigate the effect of alpha lipoic acid as antioxidant on rats with complete freund’s adjuvant (CFA)-induced RA by intra articular injection of complete freund’s adjuvant (CFA). ALA was administered orally once a day for 7 days at 30, 60 and 120 mg doses a week after CFA injection. The severity of arthritis was evaluated by joint diameter and latency time on thermal stimulation. Joint diameter and latency time on thermal stimulation will measured on day 0, 3, 5, 7, 10, 12 and 14. Measurement of malondialdehyde (MDA) level in plasma was performed using thiobarbituric acid (TBA) method to assess lipid peroxidation. Histology of joint was examined by microscope following hematoxylin-eosin staining. The result showed that treatment with ALA at 30 mg and 60 mg significantly decreased the joint diameter compared to CFA group (p=0.003; p=0.001 respectively) and rat’s latency time on thermal stimulation was also significantly increased compared to CFA group (p=0.015; p=0.026 respectively). Measurement of MDA in CFA group and ALA group had no significant difference. Histological staining indicated that the recovery of the synovial membranes of joint in ALA group had no effect. Results indicated that ALA has the effect to suppress the development of inflammation in RA but not through oxidative stress pathway.

Periodontitis increases rheumatic factor serum levels and citrullinated proteins in gingival tissues and alter cytokine balance in arthritic rats

This study investigated some immunological features by experimental periodontitis (EP) and rheumatoid arthritis (RA) disease interact in destructive processes in arthritic rats. Rats were assigned to the following groups: EP +RA; RA; EP; and Negative Control. RA was induced by immunizations with type-II collagen and a local immunization with Complete Freund's adjuvant in the paw. Periodontitis was induced by ligating the right first molars. The serum level of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACCPA) were measured before the induction of EP (T1) and at 28 days after (T2) by ELISA assay. ACCPA levels were also measured in the gingival tissue at T2. The specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for the quantification of interleukin IL-1β, IL-4, IL-6, IL-17 and TNF-α using a Luminex/MAGpix assay. Paw edema was analyzed using a plethysmometer. Periodontitis increased the RF and ACCPA levels in the serum and in the gingival tissue, respectively. Besides, the level of paw swelling was increased by EP and remained in progress until the end of the experiment, when EP was associated with RA. Greater values of IL-17 were observed only when RA was present, in spite of PE. It can be concluded that periodontitis increases rheumatic factor serum levels and citrullinated proteins level in gingival tissues and alter cytokine balance in arthritic rats; at the same time, arthritis increases periodontal destruction, confirming the bidirectional interaction between diseases.

Diastolic dysfunction in prediabetic male rats: Role of mitochondrial oxidative stress

Although incidence and prevalence of prediabetes are increasing, little is known about its cardiac effects. Therefore, our aim was to investigate the effect of prediabetes on cardiac function and to characterize parameters and pathways associated with deteriorated cardiac performance. Long-Evans rats were fed with either control or high-fat chow for 21 wk and treated with a single low dose (20 mg/kg) of streptozotocin at week 4 High-fat and streptozotocin treatment induced prediabetes as characterized by slightly elevated fasting blood glucose, impaired glucose and insulin tolerance, increased visceral adipose tissue and plasma leptin levels, as well as sensory neuropathy. In prediabetic animals, a mild diastolic dysfunction was observed, the number of myocardial lipid droplets increased, and left ventricular mass and wall thickness were elevated; however, no molecular sign of fibrosis or cardiac hypertrophy was shown. In prediabetes, production of reactive oxygen species was elevated in subsarcolemmal mitochondria. Expression of mitofusin-2 was increased, while the phosphorylation of phospholamban and expression of Bcl-2/adenovirus E1B 19-kDa protein-interacting protein 3 (BNIP3, a marker of mitophagy) decreased. However, expression of other markers of cardiac auto- and mitophagy, mitochondrial dynamics, inflammation, heat shock proteins, Ca²⁺/calmodulin-dependent protein kinase II, mammalian target of rapamycin, or apoptotic pathways were unchanged in prediabetes. This is the first comprehensive analysis of cardiac effects of prediabetes indicating that mild diastolic dysfunction and cardiac hypertrophy are multifactorial phenomena that are associated with early changes in mitophagy, cardiac lipid accumulation, and elevated oxidative stress and that prediabetes-induced oxidative stress originates from the subsarcolemmal mitochondria.

Effect of Xinfeng capsule on nuclear factor Kappa B/tumor necrosis factor alpha and transforming growth factor beta 1/Smads pathways in rats with cardiac injuries induced by adjuvant arthritis

OBJECTIVE

To investigate effects of Xinfeng capsule (XFC) on cardiac function in rats with adjuvant arthritis (AA) and explore the mechanism of these effects.

METHODS

Forty-eight rats were randomly divided into normal control (NC), model control (MC), methotrexate (MTX) and XFC groups of equal size. In all groups except for the NC group, 0.1 mL Freund's complete adjuvant (FCA) was intracutaneously injected in the right rear vola pedis to induce inflammation. Drugs were applied beginning 19 days after induction of inflammation. Normal saline was administered to the NC and MC groups and 1 mg/ 100 g MTX (weekly) and 0.12 g/100 g XFC (daily) to the MTX and XFC groups, respectively. Rats were sacrificed after 30 day of treatment. Toe swelling degree (TSD), arthritis index (Al), cardiac function and expression of nuclear factor kappa B (NF-κB)/tumor necrosis factor alpha (TNF-α) and transforming growth factor beta 1 (TGF-β1)/Smads pathway proteins were measured.

RESULTS

In the MC group, TSD and Al were greatly increased, while parameters of cardiac function were decreased and morphological analysis showed myocardial cell damage. Expression of TNF-α, NF-KB, Smad2, P-Smad2, Smad4 and TGF-β1 proteins were elevated in cardiac tissue, while Smad7 expression was decreased. TSD and Al values closely correlated to parameters of cardiac function and to levels of proteins in the NF-κB/TNF-α and TGF-β1/Smads pathways. Certain correlations were identified among TGF-β1 and NF-KB, Smad2, P-Smad2 and Smad4. With XFC intervention, both TSD and Al were decreased and parameters of cardiac function and ultrastructure of myocardial cells improved. Expressions of NF-κB, Smad2, and Smad4 proteins were greatly decreased and Smad7 expression was elevated, as compared with levels in the MC and MTX groups.

CONCLUSION

XFC regulates expression of proteins in the NF-KB/TNF-α and TGF-β1/Smads pathways, decreases immune complex deposition in cardiac tissue and improves cardiac function in AA rats via upregulation of Smad7.

Drug repositioning: playing dirty to kill pain

The number of approved new molecular entity drugs has been decreasing as the pharmaceutical company investment in research and development is increasing. As we face this painful crisis, called an innovation gap, there is increasing awareness that development of new uses of existing drugs may be a powerful tool to help overcome this obstacle because it takes too long, costs too much and can be risky to release drugs developed de novo. Consequently, drug repositioning is emerging in different therapeutic areas, including the pain research area. Worldwide, pain is the main reason for seeking healthcare, and pain relief represents an unmet global clinical need. Therefore, development of analgesics with better efficacy, safety and cost effectiveness is of paramount importance. Despite the remarkable advancement in research on cellular and molecular mechanisms underlying pain pathophysiology over the past three decades, target-based therapeutic opportunities have not been pursued to the same extent. Phenotypic screening remains a more powerful tool for drug development than target-based screening so far. It sounds somewhat heretical, but some multi-action drugs, rather than very selective ones, have been developed intentionally. In the present review, we first critically discuss the utility of drug repositioning for analgesic drug development and then show examples of 'old' drugs that have been successfully repositioned or that are under investigation for their analgesic actions. We conclude that drug repositioning should be more strongly encouraged to help build a bridge between basic research and pain relief worldwide.