Effects of intracerebroventricular injection of vitamin B12 on formalin-induced muscle pain in rats: Role of cyclooxygenase pathway and opioid receptors

A Randomized Control Trial of Dexketoprofen/Vitamin B (Thiamine, Pyridoxine and Cyanocobalamin) Fixed-Dose Combination in Post-Traumatic Grade I-II Cervical Sprains

BACKGROUND

Musculoskeletal disorders are an important cause of work absence. Clinical practice guidelines recommend nonsteroidal anti-inflammatory drugs (NSAIDs) for grade I-II cervical sprains. The combination of thiamine + pyridoxine + cyanocobalamin vitamins has been used, alone and in combination with NSAIDs, for pain and inflammation in musculoskeletal disorders.

OBJECTIVE

The objective of this study was to demonstrate the analgesic synergy of dexketoprofen, and the combination of vitamins thiamine + pyridoxine + cyanocobalamin in a fixed-dose combination (FDC) for the treatment of acute pain caused by grade I-II cervical sprains.

METHODS

We conducted a multicentre, prospective, randomized, double-blind, phase IIIb clinical study comparing two treatment groups: (1) dexketoprofen 25 mg/vitamin B (thiamine 100 mg, pyridoxine 50 mg and cyanocobalamin 0.50 mg) in an FDC (two or more active ingredients combined in a single dosage form) versus (2) dexketoprofen 25 mg monotherapy (single drug to treat a particular disease), one capsule or tablet orally, every 8 h for 7 days. Final mean, average change, and percentage change in pain perception (measured using a visual analogue scale [VAS]) were compared with baseline between groups. A p value < 0.05 was considered statistically significant. Analyses were conducted using SPSS software, v.29.0.

RESULTS

A statistically significant reduction in pain intensity was observed from the third day of treatment with the FDC compared with monotherapy (- 3.1 ± - 1.5 and - 2.6 ± - 1.1 cm, respectively) measured using the VAS (p = 0.011). Regarding the degree of disability, using the Northwick Park Neck Pain Questionnaire (NPQ), statistical difference was observed for the final measurement (7.5%, interquartile range [IQR] 2.5, 10.5; vs. 7.9%, IQR 5.0, 13.8; p = 0.028). A lower proportion of adverse events was reported when using the FDC.

CONCLUSIONS

The FDC of dexketoprofen/thiamine + pyridoxine + cyanocobalamin vitamins demonstrated superior efficacy and a better safety profile compared with dexketoprofen monotherapy for pain treatment in patients with grade I-II cervical sprains.

CLINICAL TRIALS REGISTRATION

NCT05001555, registered 29 July 2021 ( https://clinicaltrials.gov/study/NCT05001555 ).

Evaluation by different mechanisms of the protective effects of vitamin B12 on methotrexate nephrotoxicity

Methotrexate is used for cure of many cancer types. It has many side effects. For this reason, obtaining a nephroprotective agent is obligatory. In the study, our aim is to determine probable effects of Vitamin B12 on MTX caused kidney damages in rats. Rats were randomly divided into 4 groups, including 8 animals in each group. Control group, VitB12 group (3 μg-kg-ip B12 throughout 15 days), MTX group (at the 8th day of experiment, a single dose of 20 mg-kg-ip MTX), Vit B12 + MTX group (3 μg-kg-ip B12 throughout 15 days and at the 8th day of experiment, a single dose of 20 mg-kg-ip MTX) Animals were anesthetized and kidney tissues were removed to evaluate biochemically, immunohistochemically and histopathologycally. There were histopathological deteriorations, rises of apoptotic cells, expressions of heat shock proteins, endoplasmic reticulum stress and inflammation markers in the MTX group. In the MTX group, Superoxide Dismutase (SOD), Total Antioxidant Status (TAS) and Catalase (CAT) levels decreased, but Total Oxidant Status TOS, Malondialdehyde (MDA) and interleukin-6 (IL6) levels increased. In addition, there was amelioration in kidney tissue in Vit B12 + MTX group compared to the MTX group. We suggest that Vit B12 can be used to reduce the toxic effects of MTX.

Effects of intraperitoneal and intracerebroventricular injection of cinnamaldehyde and yohimbine on blood glucose and serum insulin concentrations in ketamine-xylazine induced acute hyperglycemia

This study was designed to investigate the effects of peripheral [intraperitoneal (IP)] and central [intracerebroventricular (ICV)] administration of cinnamaldehyde on concentrations of blood glucose and serum insulin in the acute hyperglycemia induced by ketamine/xylazine. Yohimbine (a α₂-adrenoceptor antagonist) was used alone and in combination with cinnamaldehyde to explore the α₂-adrenergic receptor contribution. A total of 48 rats were divided into eight groups with six rats in each for IP administration of normal saline, vehicle, cinnamaldehyde (25.00, 50.00 and 100 mg kg^-1), yohimbine (0.50 and 2.00 mg kg^-1) and cinnamaldehyde plus yohimbine. These rats were used again for ICV administration 15 days after the completion of IP experiment. During this 15 days period, the lateral ventricle of the brain was surgically cannulated for ICV administration of normal saline, vehicle, cinna-maldehyde (25.00, 50.00 and 100 µg per rat), yohimbine (5.00 and 20.00 µg per rat) and cinnamaldehyde plus yohimbine. Blood glucose levels were measured from tail blood using a glucometer and serum insulin concentrations were determined via enzyme-linked immune-sorbent assay kit. The increased levels of blood glucose and the decreased concentrations of serum insulin were significantly decreased and increased, respectively, by separate and combined IP and ICV administrations of cinnamaldehyde and yohimbine. The systemic effects of these chemical compounds were significantly greater than the central ones. Based on the results, it can be argued that cinnamaldehyde has a potential to induce anti-hyperglycemic and antihypoinsulinemic effects. Peripheral and central α₂-adrenegic receptors might be involved in these effects of cinnamaldehyde.

Therapeutic Agents for the Treatment of Temporomandibular Joint Disorders: Progress and Perspective

Temporomandibular joint disorders (TMD) are a common health condition caused by the structural or functional disorders of masticatory muscles and the temporomandibular joint (TMJ). Abnormal mandibular movement in TMD patients may cause pain, chronic inflammation, and other discomfort, which could be relieved by a variety of drugs through various delivery systems. In this study, we summarized commonly used therapeutic agents in the management of TMD as well as novel bioactive molecules in preclinical stage and clinical trials. The emerging therapy strategies such as novel intra-TMJ delivery systems and implants based on tissue engineering are also discussed. This comprehensive review will strengthen our understanding of pharmacological approaches for TMD therapy.

Medial prefrontal cortex diclofenac-induced antinociception is mediated through GPR55, cannabinoid CB1, and mu-opioid receptors of this area and periaqueductal gray

Supraspinal mechanisms of non-steroidal anti-inflammatory drug (NSAID)-induced antinociception are not well understood. In the present study, the possible antinociceptive mechanisms induced by intra-medial prefrontal cortex (intra-mPFC) microinjection of diclofenac were investigated after blockade of GPR55, cannabinoid CB1, and mu-opioid receptors in this area and ventrolateral periaqueductal gray (vlPAG). For drug delivery, unilateral (left side) of mPFC and bilateral (right and left sides) of vlPAG were surgically cannulated. Formalin test was induced by subcutaneous injection of a diluted formalin solution into the right vibrissa pad. A typical biphasic (neurogenic and inflammatory phases) pain behavior was produced following formalin injection. Microinjection of diclofenac (2.5, 5, and 10 μg/0.25 μL) into the mPFC suppressed both phases of pain. Intra-mPFC microinjection of naloxonazine (a mu-opioid receptor antagonist, 1 μg/0.25 μL) and AM251 (a cannabinoid CB1 receptor antagonist, 1 μg/0.25 μL) increased both phases of pain intensity. In addition, intra-mPFC-microinjected diclofenac-induced antinociception was inhibited by prior intra-mPFC and intra-vlPAG administration of naloxonazine and AM251. On the other hand, intra-mPFC and intra-vlPAG microinjection of AM251 (0.25 μg/0.25 μL) decreased pain severity which was inhibited by prior administration of ML193. The above-mentioned drugs did not alter locomotor activity. In conclusion, diclofenac suppressed both the neurogenic and inflammatory phases of formalin-induced orofacial pain at the level of mPFC. GPR55, cannabinoid CB1, and mu-opioid receptors of the mPFC and vlPAG might be involved in the mPFC analgesic effects of diclofenac.