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Introduction: Claw horn disruption (CHD), formerly known as subclinical laminitis (SCL), in dairy cows is the underlying syndrome leading to secondary claw lesions such as hemorrhages, sole ulcers and white line lesions. Two key events are part of current hypotheses discussed: Epidermal ischemia caused by an altered blood circulation, and epidermal glucose deficit due to a negative energy balance during the peripartal period. The aim of this study was to establish an in vitro ischemia model to investigate the epidermal response following exposure to oxygen glucose deprivation (OGD) and glucose deprivation.
Materials and Methods: Bovine claw keratinocytes were exposed to OGD or cultivated only under hypoglycaemic conditions. After exposition, cell viability was measured with LDH (lactatedehydrogenase) and MTT (3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assays. Furthermore, the differentiation pattern
of the keratinocytes was detected by western blot analysis focussing on expression of involucrin and loricrin.
Results: OGD causes the highest cytotoxic effect to the keratinocytes followed by a time-dependent decrease of cell viability. Exposure of keratinocytes to glucose deprivation showed also a high decrease of cell viability with stronger morphological hanges. Moreover, after exposure to OGD and glucose deprivation keratinocytes showed an increased expression pattern of involucrin and loricrin.
Conclusion: OGD and in particular glucose deficiency show high losses in cell viability and an altered differentiation pattern. On one hand, it represents the pathophysiological alteration subsequent to epidermal ischemia during the early pathogenesis of CHD. On the other hand, it clarifies the crucial importance of glucose in the cellular metabolism of epidermal keratinocytes and establishes a link between keratinocyte metabolism and the pathophysiological changes during negative energy balance. This in vitro ischemia model based on bovine claw keratinocytes is a novel powerful tool to study the physiological mechanisms in epidermis as well as the epidermal pathomechanisms in CHD.