The Effect of Loading Frequency on Tenocyte Metabolism
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Achilles tendinopathy is a prevalent, highly debilitating condition. It is believed to result from
repetitive overuse, which creates micro-damage tendon, and initiates a catabolic cell response.
The aetiology of tendinopathy remains poorly understood, therefore appropriate treatment
remains unclear.
Current data support the use of shock wave therapy and eccentric exercise as some of the more
effective treatment options for tendinopathy. Studies have shown that these treatments generate
perturbations within tendon at a frequency of approximately 8-12Hz. Consequently, it is
hypothesised that 10Hz loading initiates increased anabolic tenocyte behaviour promoting
tendon repair. The primary aim of this thesis is to investigate the effects of 10Hz perturbations
on tenocyte metabolism, comparing tenocyte gene expression in response to a 10Hz and 1Hz
loading profile.
A variety of in vitro models for mechanically stimulating cells were explored, comparing tissue
explants with isolated cells on a 2D or within a 3D collagen gel. The mechanical environment
of each model was investigated, in addition to cell viability and gene stabilisation following
strain, as needed for future cell studies. 3D collagen gels arose as the most suitable model.
Human tenocytes from healthy semitendinosus and tendinopathic Achilles tendons were
seeded into 3D collagen gels and subjected to cyclic strain at 10Hz and 1Hz to establish cell
response. Tenocyte gene expression was characterised using qRT-PCR.
Healthy tenocytes showed increased expression of all analysed genes in response to loading.
Furthermore, the increase was significantly larger in the 10Hz loading group. Tendinopathic
tenocytes showed a more varied response, possibly indicative of an early healing response.
Nevertheless, the response to 10Hz loading was consistently greater than seen with 1Hz
loading. Analysis of the signalling pathways involved suggested that the IL1 signalling
pathway may be involved in the strain response reported.
This study has demonstrated for the first time that loading at a frequency of 10Hz may enhance
metabolic response in healthy tenocytes.
Authors
Udeze-Jyambere, Chineye PrincessCollections
- Theses [4248]