Local and systemic responses to repeated gluteal muscle microbiopsies in mature sedentary horses.
Authors: Artman Jessica L, Wesolowski Lauren T, Semanchik Pier L, Isles JadaLea K, Norton Sharon A, White-Springer Sarah H
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Repeated Gluteal Muscle Biopsies in Horses Researchers collected multiple gluteal muscle biopsy samples from 26 mature horses over 24 hours, combined with blood sampling every 6 hours for 72 hours, to determine whether the sampling procedure itself caused measurable physiological stress responses including mitochondrial dysfunction, oxidative stress, or inflammatory changes. Early responses were largely transient: complex II electron transfer capacity declined and mitochondrial leak respiration increased within 6 hours of biopsy, but both parameters normalised by 12 hours, whilst serum creatine kinase rose in all horses at 6 hours and remained elevated through 48 hours despite staying within reference ranges. Beyond these initial markers, the study found no meaningful alterations in mitochondrial function, antioxidant status, inflammatory cytokines, acute phase proteins, or cortisol levels—responses remained independent of biopsy frequency or timing. For equine professionals collecting muscle biopsies in clinical or research settings, these findings suggest the procedure causes minimal systemic stress in calm, mature horses, though the serum CK elevation warrants careful interpretation if biomarkers are being used to assess muscle damage or exertional myopathy separately from biopsy-induced effects. The data support repeated safe sampling from the gluteus medius in sedentary horses, though extrapolation to exercise-stressed or young animals would require further investigation.
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Practical Takeaways
- •Repeated gluteal muscle biopsies in mature sedentary horses are well-tolerated with minimal physiological disruption, making them safe for research and clinical assessment protocols
- •Serum CK elevation following biopsies is expected but remains within normal limits; practitioners should not over-interpret mild CK elevations during repeated tissue collection protocols
- •Mitochondrial and metabolic function returns to baseline within 12 hours of biopsy, supporting the feasibility of serial muscle sampling without compromising cellular integrity
Key Findings
- •Complex II electron transfer capacity decreased at 6h post-biopsy but returned to baseline by 12h (P=0.004)
- •Serum creatine kinase activity increased in all horses at 6h and remained elevated through 48h but remained within reference ranges (P<0.05)
- •Citrate synthase activity was significantly greater at 0h compared to 12 and 24h (P≤0.02)
- •Repeated gluteal muscle collections had limited short-term or no effect on physiological markers including mitochondrial capacities, antioxidant status, cytokines, and serum amyloid A in unstressed mature horses