Differential regulation of protein synthesis in smooth muscle cells from normotensive and spontaneously hypertensive rats by a three-dimensional matrix of type I collagen.

Abstract

The objective of this study was to gain insight into the metabolic and morphological properties of smooth muscle cells (SMC) from spontaneously hypertensive rats (SHR) when cultured in vivo under similar conditions. Three-dimensional cell-collagen systems represent living tissue equivalents in vitro and simulate natural conditions more closely than conventional monolayer cultures. The effect of a three-dimensional matrix of type I collagen on ultrastructure, total protein and collagen synthesis and cell cycle distribution of SMC from SHR and normotensive Wistar-Kyoto (WKY) rats was studied. Collagen lattice-cultured SMC from SHR and WKY rats showed the synthetic phenotype, i.e. the cytoplasm was filled with organelles characteristic of secretory protein synthesis. There was a decrease in the percentage of cells in the 5 phase compared with monolayer cultures. Total protein synthesized by SMC from SHR and WKY rats in lattices was lowered compared with monolayer cultures. However, reduction of protein synthesis in SMC from SHR was less than in SMC from WKY rats. Differences in the proportion of collagen in SMC from SHR and WKY rats were not demonstrable in collagen lattice cultures. The present study suggests that a three-dimensional matrix of type I collagen may modulate total protein synthesis in SMC from SHR and WKY rats. However, cells from SHR react less to this matrix than those from WKY rats.