Investigation of Cow Bone Tissue Structure: Govju kaulaudu struktūras pētījumi

Bone routine morphology and factors able to influence bone structure in dairy cows were investigated.
Humerus bone in 5-6 years old lactating cows was examined after compulsory slaughtering of cows. The Cutting-Grinding Technique for Hard Tissue was used for dissection of bone. Mineral density test was used for cow bone investigation too. Growth factors BMP2/4 and FGFR were used to detect cell growth and cellular differentiation by immunohistochemistry (IMH). TUNEL method was performed to detect cell death. MMP2 and MMP9 IMH detection was used for matrix degradation. Bone showed thin trabecules with the number of osteocytes varying from 20.30±3.79 to 54.30±5.66 per mm2. Osteones also presented different diameter – from 0.0668±0.0183 to 0.1596±0.0285 mm. Intensive proliferation of connective tissue and small capillaries was seen in osteon channels. Regions with granular, optically intensively stained basophilic substance were observed here and there in bone with density from 2206.45±714 to 3017.94±744 g cm-2. Fragments of articular cartilage seemed not changed in routine histological sections. Few BMP2/4-containing cells were detected in all chondrocytes of articular cartilage in all animals and in main part of bone of cows. Numerous to abundance of chondrocytes expressed FGFR1 in articular cartilage, but only few osteocytes of spongy bone contained these receptors. Total apoptosis affected mainly chondrocytes. Both matrix metalloproteinases degraded the cartilage. Bone of healthy dairy cows demonstrated various number of osteocytes and diameter of osteones, and different bone density. Proliferation of connective tissue and small capillaries in osteon channels indicated regional osteoporosis. BMPs were expressed in articular cartilage. The articular cartilage is more affected by apoptosis and FGFR and MMP expression.