paper 4 summary

Figure 3 shows the same pattern as those seen in our experiment. The two markers that the researchers that were used to measure cell proliferation are Ki67 and BrdU. Ki67 is a protein that is highly expressed in cells that are proliferating. Ki67 labels cells that are in M, G1,S, and G2 phases. However, because the only cells that do not express the protein are cells in G0, there are many cells that would be positive for this marker. BrdU is extremely similar to EdU in how they mark cells that are proliferating. Unlike Ki67, BrdU and EdUmarkers only mark's cells that are undergoing S phase, as a result, it is more specific. However, BrdU is an antibody compared to EdU which is a click it reaction and incorporates thymidine analog into the DNA.  In hyperthyroid conditions, A2B5 was upregulated in the mitral cell layer compared to the control, and also had a positive cell in other layers of the olfactory bulb. There is a decrease in MBP protein expression in the optic nerve of hypothyroid rats. The conclusion that I can draw about the effect of thyroid hormone on oligodendrocyte progenitors and mature oligodendrocytes is thyroid hormones regulate something upstream of pre oligodendrocyte and mature oligodendrocyte. This conclusion can be drawn because the thyroid hormone is increasing preoligodendroctyes in hyperthyroid conditions which indicates that there are more preoligodendrocytes in hyperthyroid conditions. The decrease in MBP protein suggests that there is a decrease in mature oligodendrocytes.  From these two pieces of information, no conclusion can be drawn since they are in different parts of the brain and indicate two different types of cell regulation. However, since the paper mentions that there is an increase in MBP protein in hyperthyroid condition and a decrease or no change in hypothyroid condition, as well as that A2B5 is not observed in hypothyroid brains. Using this information, I can predict that the thyroid hormone regulates something that is upstream of pre oligodendrocyte. However, using the information that is just given, no conclusion can be reached because a decrease of thyroid hormone should have an opposite effect and that is not seen as clearly here.