# Alpinetin protects against iron overload related osteoarthritis via NRF2/HO-1 pathway

## TL;DR

Alpinetin protects against osteoarthritis caused by iron overload by activating the NRF2/HO-1 pathway, reducing cartilage damage and oxidative stress.

## Contribution

This study is the first to demonstrate that alpinetin can protect against iron overload-induced osteoarthritis via the NRF2/HO-1 pathway.

## Key findings

- Alpinetin reduced chondrocyte apoptosis and ROS accumulation in iron overload models.
- Alpinetin upregulated antioxidant genes NRF2 and HO-1, improving cartilage viability.
- In vivo experiments showed alpinetin attenuated cartilage damage and subchondral bone proliferation.

## Abstract

Alpinetin(APT) is a natural product with anti-inflammatory and antioxidant effects. Iron overload has been recognized in recent years as a new way to exacerbate osteoarthritis.

This study evaluated the effects of ATP on iron overload related osteoarthritis.

C57BL/6J mice were randomly allocated to five groups as follows (n = 10 mice each): (1) sham; (2) destabilized medial meniscus(DMM); (3) DMM + ID; (4) DMM + ID + APT-L (50 mg/kg APT gavage daily); (5) DMM + ID + APT-H (100 mg/kg APT gavage daily). The chondrocytes treated by FAC (100μM) were used as an in vitro model of iron overload and the effect of APT was observed. Flow cytometry, fluorescence microscopy, Western blot, qRT-PCR and micro-CT were used to detect the mechanism of action of the APT.

Our studies showed that APT improved the viability of chondrocytes induced by iron overload. APT can reduce apoptosis of chondrocytes (19.41 ± 2.12% vs. 9.82 ± 1.74%). Furthermore, APT was found significantly attenuated ROS accumulation (2.04 ± 0.31 vs. 1.44 ± 0.15-fold) of chondrocytes through upregulating antioxidant genes NRF2 (1.18 ± 0.13 vs. 1.55 ± 0.17-fold) and HO-1 (1.27 ± 0.15 vs. 1.77 ± 0.20-fold). In vivo experiments revealed that APT attenuated cartilage damage (OARSI score 5.75 ± 1.32 vs. 3.75 ± 0.96) and subchondral bone proliferation in iron overload osteoarthritis mice.

Our results show that APT can attenuate iron overload-induced cartilage damage in vivo and in vitro via the NRF2/HO-1 pathway. We demonstrated for the first time that APT has promising applications in iron overload diseases.