Three-dimensional reconstruction of juxtaglomerular apparatus (JGA) in five-sixth nephrectomized rats

In Wistar male rats, hypertension was induced by five-sixth nephrectomy (5/6N). Body weight, systolic blood pressure (SBP) and plasma renin concentration (PRC) were followed for 12 weeks after 5/6N. Three-dimensional reconstruction and morphometry of the JGA were carried out using a computer program "GLOM". Immunohistochemistry and electron microscopy of the JGA were also investigated. A statistically significant increase in SBP was shown after 5/6N. However, PRC showed no increase and was not correlated with SBP. Renin-containing cells were demonstrated in the afferent and efferent arterioles and the interlobular arteries. Electron microscopy revealed granules of various shapes, sizes and electron densities within the JG cell. The frequency of granulated cells in the efferent arteriole was less than that in the afferent arteriole. The afferent arteriole wall volume of 5/6N rats was significantly increased and positively correlated with SBP. The lack of relationship between PRC and SBP in this model suggests that mechanisms other than the renin-angiotensin system may be involved in the pathogenesis of hypertension.