Oxygen free radicals affect Dupuytren’s fibroblasts: high levels are toxic, but not only do slightly elevated levels stimulate fibroblast activity, active fibroblasts actually produce oxygen free radicals. Which is the chicken and and which is the egg? This seminal paper reports studies of the effects of oxygen free radicals on Dupuytren and normal fibroblasts, the effect of blocking free radicals with free radical scavengers, and brings up the relationship between mechanical forces, oxygen free radicals and abnormal fibroblast proliferation in Dupuytren’s: http://www.dupuytrenfoundation.org/DupPDFs/1990_Murrell_1203.pdf. Cause and effect? We still need to know – more work to do.