Cinnamic acid prevents skeletal muscle atrophy in nephrectomized rats by modulating apoptosis and endoplasmic...

Skeletal muscle atrophy is frequently observed in patients with chronic kidney disease (CKD), exacerbating disease progression and diminishing patients' quality of life. Cinnamic acid (CINN), a low-toxicity phenolic acid derived from Cinnamomum cassia (L.) J. Presl, remains uncharacterized in terms of its efficacy and mechanism against CKD-induced skeletal muscle atrophy.

To assess the protective impact of CINN on skeletal muscle atrophy in CKD rats and elucidate its potential molecular mechanisms.

A 5/6 nephrectomy (5/6 Nx) rat model was constructed and treated with varying concentrations of CINN via gavage. Potential targets and pathways of CINN were identified using network pharmacology and validated through transmission electron microscopy, TUNEL staining, quantitative real-time PCR, and western blot analysis. To confirm whether CINN's therapeutic effects depended on its interaction with the identified target, in vitro experiments employed specific inhibitors to reverse the observed effects.

CINN therapy enhanced body and muscle mass, serum albumin concentrations, and various clinical markers. Western blot analysis revealed that CINN inhibited protein proteolysis and promoted protein synthesis in the 5/6 Nx group. Network pharmacology and experimental validation indicated that CINN may alleviate skeletal muscle atrophy by reducing apoptosis and endoplasmic reticulum stress through targeting heat shock protein 90 alpha family class A member 1 (HSP90AA1). In vitro experiments using an HSP90AA1 antagonist demonstrated that the muscle-protective effects of CINN were partially reversed when HSP90AA1 was inhibited.

CINN may alleviate CKD-induced skeletal muscle atrophy by inhibiting apoptosis and endoplasmic reticulum stress via its action on HSP90AA1.