Characterisation of nociception and inflammation observed in a traumatic muscle injury model in rats

Involvement of the Transient Receptor Channels in Preclinical Models of Musculoskeletal Pain

BACKGROUND

Musculoskeletal pain is a condition that affects bones, muscles, and tendons and is present in various diseases and/or clinical conditions. This type of pain represents a growing problem with enormous socioeconomic impacts, highlighting the importance of developing treatments tailored to the patient's needs. TRP is a large family of non-selective cation channels involved in pain perception. Vanilloid (TRPV1 and TRPV4), ankyrin (TRPA1), and melastatin (TRPM8) are involved in physiological functions, including nociception, mediation of neuropeptide release, heat/cold sensing, and mechanical sensation.

OBJECTIVE

In this context, we provide an updated view of the most studied preclinical models of muscle hyperalgesia and the role of transient receptor potential (TRP) in these models.

METHODS

This review describes preclinical models of muscle hyperalgesia induced by intramuscular administration of algogenic substances and/or induction of muscle damage by physical exercise in the masseter, gastrocnemius, and tibial muscles.

RESULTS

The participation of TRPV1, TRPA1, and TRPV4 in different models of musculoskeletal pain was evaluated using pharmacological and genetic tools. All the studies detected the antinociceptive effect of respective antagonists or reduced nociception in knockout mice.

CONCLUSION

Hence, TRPV1, TRPV4, and TRPA1 blockers could potentially be utilized in the future for inducing analgesia in muscle hypersensitivity pathologies.

Targeting of cold-inducible RNA-binding protein alleviates sepsis via alleviating inflammation, apoptosis and oxidative stress in heart

A systemic inflammatory response is observed in patients undergoing shock and sepsis. This study aimed to explore the effects of cold-inducible RNA-binding protein (CIRP) on sepsis-associated cardiac dysfunction and the underlying mechanism. In vivo and in vitro lipopolysaccharide (LPS)-induced sepsis models were established in mice and neonatal rat cardiomyocytes (NRCMs), respectively. CRIP expressions were increased in the mouse heart and NRCMs treated with LPS. CIRP knockdown alleviated LPS-induced decreases of left ventricular ejection fraction and fractional shortening. CIRP downregulation attenuated the increases of inflammatory factors in the LPS-induced septic mouse heart, and NRCMs. The enhanced oxidative stress in the LPS-induced septic mouse heart and NRCMs was suppressed after CIRP knockdown. By contrast, CIRP overexpression yielded the opposite results. Our current study indicates that the knockdown of CIRP protects against sepsis-induced cardiac dysfunction through alleviating inflammation, apoptosis and oxidative stress of cardiomyocytes.

Effect of Phonophoresis and Copaiba Oil on Oxidative Stress Biomarkers after Skeletal Muscle Injury in Rats

The objective of this study was to analyze the effectiveness of phonophoresis with copaiba oil gel, in comparison to therapeutic pulsed ultrasound alone or topical application of copaiba oil gel, on oxidative stress after a traumatic muscle injury. Forty male Wistar rats were divided into five groups: control, muscle injury, therapeutic pulsed ultrasound (TPU), copaiba oil gel (CO) and TPU plus CO. TPU and CO application occurred at 2, 12, 24, 48, 72 and 96 h after injury. The gastrocnemius muscle was injured by mechanical trauma. Malondialdehyde (a lipoperoxidation marker) and superoxide dismutase and catalase (antioxidant enzymes) were assessed 98 h after muscle injury. All were elevated in the muscle injury group. There was a significant difference among treatment groups favoring TPU plus CO for reducing malondialdehyde levels, but all treatments reduced superoxide dismutase and catalase activity, with no between-groups difference. In conclusion, phonophoresis-the application of TPU plus CO-was superior to TPU or CO alone for reducing lipoperoxidation. Phonophoresis, TPU alone and CO were all effective in decreasing antioxidant enzyme activity after a traumatic skeletal muscle injury.