Abstract
Objective: As an aberrant response to cutaneous wound healing, keloid scarring is a challenge to cure, and its clinical management remains unsatisfactory. The purpose of this study was to investigate whether mitochondrial function and morphology were impaired in keloid pathology. Approach: Keloid fibroblasts (KFs) and normal skin fibroblasts (NFs) were isolated and cultured from excised samples. A real-time extracellular flux analyzer was used to monitor the oxygen consumption rate for evaluating the mitochondrial respiratory function. Real-time PCR or Western blot was performed to detect the levels of mRNAs or proteins, respectively, including those associated with the tricarboxylic acid cycle, mitochondrial fission and fusion, and mitochondrial biogenesis. The reactive oxygen species (ROS) level and the mitochondrial mass were measured by flow cytometry. Mitochondrial ultrastructure was observed by transmission electron microscopy. Results: Compared with NFs, KFs showed reduced basal oxidative respiration (p < 0.05), maximal oxidative respiratory capacity, ATP production, and coupling efficiency (p < 0.01) but increased proton leakage (p < 0.01). ROS were decreased (p < 0.05) in KFs, whereas the mitochondrial mass was increased (p < 0.01). The mRNA and protein expressions related to mitochondrial dynamics (fission and fusion) and biogenesis were significantly upregulated in KFs (p < 0.05). Mitochondria in both KFs and keloid tissue were distended and swollen, along with displaying vacuolization and effacement of the cristae. Innovation: The possible involvement of mitochondrial abnormities in keloid pathology may promote promising therapeutic strategies for wound healing disorders. Conclusion: Collectively, our data suggested that both mitochondrial dysfunction and morphological impairment might play vital roles during keloid pathogenesis.