Figure 1 Icariin attenuates renal function and histological
damage in UUO mice. (A) The chemical structure of icariin. (B)
Experiment outline. (C) Weight changes after 14 days of UUO surgery.
(D-E) Serum BUN and Cr levels in different group. (G) Representative
images of H&E and Masson’s staining, and quantitative assessment of
renal injury (F) and fibrosis (H). (I) Western blot analysis of collagen
I and α-SMA expression in the kidney from different groups. BUN, blood
urea nitrogen; Cr, creatinine. * p < 0.05, ** p <
0.01.
Icariin alleviated inflammatory responses and oxidative stress
in UUO mice.
To explore the underlying mechanism of icariin therapy, transcriptome
sequencing was applied. According to results of the Gene Ontology (GO)
term analysis between the sham and UUO mice, the differentially
expressed genes exhibited strong enrichment in inflammatory response and
oxidoreductase activity (Figure 2A). Considering that inflammation and
oxidative stress are well-documented contributors in the development of
interstitial fibrosis, the present research centered on the impact of
icariin on pivotal genes within the enriched gene sets related to
inflammatory response and oxidoreductase activity. As shown in Figure
2B, icariin reduced inflammatory response-related gene expression
profiles. In addition, the mRNA expression of inflammatory factors
IL-1β, IL-6 and TNF-α in kidneys were examined by quantitative real-time
PCR to further validate the sequencing results. As expected, all these
factors demonstrated a significant rise in the obstructed kidneys of UUO
group, but were notably reduced following icariin treatment (Figure 2D).
Moreover, we analyzed inflammatory cell infiltration of renal tissue by
immunostaining of F4/80 and found significantly fewer F4/80-positive
macrophages in icariin-treated mice than in sham group (Figure 2G).
The heatmap of oxidoreductase-related gene levels revealed that icariin
reversed UUO-induced alterations of important oxidoreductase and
improved redox balance (Figure 2C). Next, we investigated the levels of
MDA, a lipid peroxidation product that is associated with pathological
changes in reaction to oxidative stress, and the activity of endogenous
SOD in kidney tissue (Figure 2E,F). As a result, we observed
significantly increased MDA content and reduced activity of SOD in the
obstructed kidneys of UUO mice. Interestingly, treatment with icariin
reduced the MDA content and restored the SOD activity, suggesting that
the oxidative stress was effectively alleviated by icariin. Taken
together, these data demonstrate that icariin can relieve inflammation
and oxidative stress, thereby delaying TIF in UUO mice.