Comparison of Northern blot hybridization and a reverse transcriptase-polymerase chain reaction technique for measurement of mRNA expression of metalloproteinases and matrix components in articular cartilage and synovial membrane from horses with osteoarthritis.

The research article presents a comparative study of the use of Northern blot hybridization and a reverse transcriptase-polymerase chain reaction (RT-PCR) technique for measuring mRNA expression of certain proteins and components involved in osteoarthritis in horses.

About The Research

• In this study, researchers are attempting to accurately measure the mRNA expression of aggrecan, type-II collagen, matrix metalloproteinase (MMP) 1, and MMP3. These components play crucial roles in joint health and are often associated with conditions such as osteoarthritis (OA).
• The subjects were articular cartilage and synovial membrane samples derived from eight pairs of equine joints, with one joint with osteoarthritis and one healthy pair from each of six horses.
• Additionally, synovial membrane samples were also gathered from six pairs of joints from five horses. Articular cartilage is a connective tissue that coats the surface of joints, while synovial membrane encloses the joint cavity and secretes synovial fluid that reduces friction in joints during movement.
• The overall objective was to compare the efficiency of Northern blot hybridization with that of a RT-PCR assay in quantifying mRNA expression of the aforementioned components.

Methods and Findings

• The researchers extracted RNA from the joint samples using a modified Trizol procedure, and then applied Northern blot hybridization and RT-PCR.
• They found that articular cartilage samples from joints with mild or moderate osteoarthritis yielded less total RNA than samples from joints with severe OA.
• Northern blot hybridization revealed that type-II collagen mRNA expression in OA cartilage samples was significantly higher than in healthy samples. However, when using the RT-PCR assay, they were able to identify low levels of MMP3 mRNA expression in four sets of articular cartilage and synovial membrane samples.
• On the contrary, Northern blot hybridization only detected MMP3 mRNA expression in one set of the same samples. This significant variance in results led the researchers to conclude that the RT-PCR assay is more sensitive than Northern blot hybridization, and additionally requires smaller samples.

Implications of the Findings

• The higher sensitivity of the RT-PCR assay in detecting mRNA expressions gives it a clear advantage over Northern blot hybridization, as it may allow for earlier detection of osteoarthritis through monitoring shifts in the expression levels of aggrecan, type-II collagen, MMP1, and MMP3.
• Moreover, requiring smaller samples makes RT-PCR assay a less invasive method, which is important in the field of veterinary medicine, for the welfare of the animals under study.