Type VII and XVII Collagen mRNA Expressions in Regenerated Epidermal Laminae in Chronic Equine Laminitis

To confirm ability forming the basement membrane of the regenerated laminar epidermis (rLE) in chronic laminitis, expression of type VII and type XVII collagen mRNAs in the rLE was studied applying sequences of two type of murine collagens. On northern blot analysis, complement DNA (cDNA) probes adjusted from the murine type VII and type XVII collagen could hybridize with the equine mRNAs, and each signal was detected as single-bands at approximately 9.5 kb and 5.6 kb, respectively. Contrasting with the expression level of equine glyceraldehyde-3-phosphate dehydrogenease mRNA, the band of type VII collagen mRNA in laminitis was stronger than normal, but the type XVII collagen mRNA in laminitis was less than normal. By in situ hybridization, positive signals in response to the murine type VII and type XVII collagen mRNA probes could be detected in the equine laminitic rLE region. From these results, it is concluded that the keratinocytes constructing the rLE in chronic stage of laminitis can express type VII and type XVII collagen mRNAs and these expression patterns were different from the normal.