FN1 and renal fibrosis: Fog et al. [10] showed that the levels of serum HA, C-IV, LN, and FN indicators could reflect the degree of renal fibrosis, and the higher the levels of HA, LN, and C-IV indicators, the more serious the renal fibrosis, and the lower the level of serum FN indicators that also represents the severity of renal fibrosis.