Correlation between oxidative stress and inflammation with metabolomics profile in skeletal muscle of ageing animal model and its modulation by tocotrienol-rich fraction

Ageing muscle is under siege from within. As skeletal muscle grows older, it becomes a battleground where reactive oxygen species overwhelm antioxidant defences, chronic low-grade inflammation smoulders, and DNA lesions accumulate. A new study from Universiti Kebangsaan Malaysia, published in the British Journal of Biomedical Science, has now mapped these destructive processes onto the metabolic fingerprint of ageing muscle and tested whether a potent form of vitamin E could rewrite the script. The findings suggest that tocotrienol-rich fraction, known as TRF, acts less like a muscle builder and more like a molecular peacemaker, restoring balance across interconnected redox, inflammatory, and metabolic networks before irreversible damage takes hold.

Sarcopenia, the age-associated decline in skeletal muscle mass and function, affects between 5 and 13 percent of people aged 60 to 70, rising dramatically to between 11 and 50 percent in those over 80. The condition is driven by multiple converging mechanisms, chief among them oxidative stress, chronic inflammation, and genomic instability. When reactive oxygen species production outpaces the body’s antioxidant capacity, the resulting imbalance damages mitochondrial membranes, impairs cellular metabolism, and activates apoptotic signalling pathways that lead to muscle cell death. Simultaneously, chronic low-grade inflammation, termed inflammaging, disrupts muscle protein synthesis and regeneration, creating a vicious cycle of degeneration that accelerates functional decline.

The research team, led by Siti Liyana Saud Gany and corresponding author Suzana Makpol, designed their experiment around young and old male Sprague-Dawley rats aged 3 and 21 months respectively. Forty animals were divided into control and TRF-supplemented groups, with 10 rats per subgroup. The supplemented groups received TRF orally at 60 milligrams per kilogram of body weight per day over 3 months, while control animals received refined, bleached, and deodorized palm olein. Only male rats were used to minimise hormonal variability that could confound oxidative stress and metabolic measurements. At the end of the supplementation period, gastrocnemius and soleus muscles were excised, rapidly frozen, and stored for subsequent biochemical, histological, and metabolomic analysis.

The investigators quantified a comprehensive panel of oxidative stress and inflammatory markers, including superoxide dismutase and catalase activities, lipid peroxidation products malondialdehyde and 4-hydroxynonenal, C-reactive protein, interleukin-6, tumour necrosis factor alpha, and prostaglandin F2-alpha. DNA damage was assessed using the comet assay, a sensitive single-cell electrophoresis technique that measures DNA fragmentation through parameters such as tail length, tail DNA percentage, tail moment, and olive moment. Muscle histology was examined using hematoxylin and eosin staining to evaluate connective tissue thickness and nuclear infiltration. The metabolomics data, derived from an untargeted liquid chromatography-mass spectrometry platform in a companion publication, were then correlated with these biological markers using Pearson correlation analysis to reveal network-level interactions rather than isolated endpoints.

Ageing left an unmistakable molecular signature. Old control rats showed significantly elevated oxidative damage, increased pro-inflammatory markers, and greater DNA fragmentation, alongside reduced antioxidant enzyme activities and disrupted metabolic profiles. Dual-energy X-ray absorptiometry confirmed hallmark features of ageing body composition, including increased fat percentage and fat mass, and reduced lean mass in older animals. Histological examination revealed thicker connective tissue surrounding muscle fibres in old control animals and numerous nuclei infiltrating muscle fibres in the gastrocnemius of aged controls, signs consistent with degeneration and attempted regeneration. These findings collectively demonstrate that ageing muscle exists in a state of coordinated biological dysregulation across multiple systems simultaneously.

Although TRF supplementation did not significantly restore muscle mass or reverse overall body composition decline, its effects on molecular and cellular markers were striking. Supplementation significantly increased superoxide dismutase and catalase activities in aged rats, reduced malondialdehyde and 4-hydroxynonenal levels compared with aged controls, attenuated inflammatory responses, preserved DNA integrity, and improved muscle histological features. The reduction in connective tissue thickness and absence of nuclear infiltration in supplemented animals provided visual evidence of TRF’s cytoprotective capacity. These results indicate that TRF primarily exerts preventive rather than anabolic effects, supporting cellular homeostasis and mitigating molecular damage rather than directly promoting muscle hypertrophy or reversing established structural decline.

The correlation analyses revealed something particularly compelling about how ageing reshapes metabolic networks. In aged control rats, strong positive correlations between catalase activity and metabolites such as histidine, pantothenic acid, and 3-methylhistidine pointed to an adaptive antioxidant response driven by damage, wherein increased oxidative stress simultaneously promotes muscle protein breakdown, metabolic adaptation, and enzyme upregulation. This pattern is characteristic of sarcopenic muscle, where chronic oxidative stress couples proteolysis with compensatory antioxidant defences. In contrast, TRF supplementation substantially altered these relationships, weakening the maladaptive biomarker-metabolite associations while strengthening correlations between protective metabolites and antioxidant enzymes.

Specific metabolites emerged as key players in TRF’s network-level modulation. Carnosine, a histidine-containing dipeptide abundant in skeletal muscle, showed strong negative correlations with malondialdehyde in supplemented aged animals, suggesting that higher carnosine availability is linked to reduced lipid peroxidation. Carnitine species, essential for mitochondrial fatty acid transport, also displayed inverse relationships with oxidative damage markers. Taurine, highly enriched in skeletal muscle where it regulates ion channel function and supports mitochondrial quality control, showed negative correlations with DNA damage indices in supplemented aged rats, indicating a possible enhancement of its DNA-protective role through supplementation. Pyroglutamic acid, an intermediate of the gamma-glutamyl cycle, showed positive associations with superoxide dismutase activity, suggesting tighter coupling between glutathione cycling and superoxide detoxification under TRF.

The inflammatory metabolite correlations told a complementary story. In young supplemented rats, prostaglandin F2-alpha displayed significant negative correlations with L-acetyl carnitine and glutamine, suggesting supplementation-related modulation of inflammatory signalling through enhanced mitochondrial bioenergetics and antioxidant defence support. In aged supplemented animals, the shift towards positive associations between prostaglandin F2-alpha and pyroglutamic acid or spermine reflected heightened metabolic activity in response to inflammation, indicating adaptive compensatory mechanisms. Aged control rats exhibited weak or disrupted correlations between inflammatory markers and metabolic indicators, consistent with impaired metabolic responsiveness and flexibility that characterises chronic inflammaging.

These findings collectively reposition TRF beyond its conventional role as a direct antioxidant. The data suggest that TRF acts primarily as a preventive intervention by restoring redox balance, dampening inflammatory signalling, and stabilising metabolic and inflammatory coupling across interconnected biological networks. Rather than simply scavenging free radicals, TRF appears to modulate the broader redox-metabolic milieu underlying ageing and sarcopenia, shifting the system from a predominantly damage-driven state toward a more regulated and resilient metabolic environment. The authors acknowledge limitations including the relatively brief supplementation duration, the absence of functional muscle performance assessments such as grip strength, and the use of only male rats, which may not capture sex-specific differences in redox regulation and metabolic response. Nevertheless, this study represents an advance in biomedical science by demonstrating that a nutritional strategy can stabilise the complex interactions between metabolomics, oxidative stress, inflammation, and genomic stability during ageing, offering a promising avenue for preserving muscle health and cellular integrity in older adults.

Subject of Research: Correlation between oxidative stress and inflammation with metabolomics profile in skeletal muscle of ageing animal model and its modulation by tocotrienol-rich fraction

Article Title: Correlation between oxidative stress and inflammation with metabolomics profile in skeletal muscle of ageing animal model and its modulation by tocotrienol-rich fraction

Article References: Saud Gany, S. L., Mohd Sahardi, N. F. N., Tan, J. K., & Makpol, S. (2026). Correlation between oxidative stress and inflammation with metabolomics profile in skeletal muscle of ageing animal model and its modulation by tocotrienol-rich fraction. British Journal of Biomedical Science, 83, Article 16208. https://doi.org/10.3389/bjbs.2026.16208

Image Credits: AI Generated

DOI: 10.3389/bjbs.2026.16208

Keywords: Correlation, between, oxidative, stress, inflammation, metabolomics, profile, skeletal, muscle, ageing, animal, model