Hypoxia in fibroblast cultures. 2. Influence of pH on the distribution pattern of acid mucopolysaccharides.

Secondary cultures of embryonic rat fibroblasts [NEUPERT et al., Exp. Path. 7, 19-28 (1972)] were cultured in 21% and 5% O2 concentration at pH 6.6 and 7.4 for 6 or 8 days. The acid mucopolysaccharides were isolated and fractionated by alcohol precipitation, papain digestion, CPC-precipitation and fractionation after the microtechniques of SVEJCAR and ROBERTSON [see KITTLICK and NEUPERT, Exp. Path. 7, 7-18 (1972)]. Cells and medium were investigated together. The results were related to cell density and compared with the glucose and lactate values [see KITTLICK and NEUPERT, Exp. Path. 10, 109-114 (1975)]. Concerning the question of interrelations of MPS-synthesis and glycolysis a survey on literature is given. Our own test results were as follows: 1. Hypoxia (5% O2) did not influence MPS-total synthesis. 2. Depending on cell density the individual MPS fractions were different in their reaction to hypoxia. 3. Hyaluronic acid (and heparan sulphate) in the MPS-pattern showed other behaviour than chondroitin sulphate and dermatan sulphate, respectively. 4. At low cell density hypoxia effectuated increase in hyaluronic acid and decrease in chondroitin sulphate and dermatan sulphate, respectively. 5. At high cell density hypoxia effectuated decrease in hyaluronic acid and increase in chondroitin sulphate and dermatan sulphate, respectively. Possible relationship to processes in the tissue is discussed.