Figure 1.

Effects of postnatal thyroid hormone deficiency on microvessels in the neocortex. Postnatal hypothyroidism was induced with PTU in the drinking water from birth to P21. Immunohistochemistry staining of mouse anti-RECA (microvessel marker) showed visible changes in the cortical microvessels at P21 in the PTU-treated rats (A and B), with full recovery by P90 (C and D). Quantitative analysis of cortical microvessels was based on several parameters: branching point (E), microvessel density (F), and microvessel diameter (G) in 40-μm-thick, sagittal sections. At P21, PTU treatment resulted in decreased branching points, decreased microvessel density, and enlarged microvessel diameter. However, by P90, these changes were no longer apparent. Data are presented as mean±s.e.m. from P21 (n=8) and P90 rats (n=16, 8 male and 8 female). Two-sample equal variance t-test was applied, ^**P<0.01. Scale bar in panel A=50 μm.