Related Experiment Video
Updated: Oct 19, 2025

Creation of a Knee Joint-on-a-Chip for Modeling Joint Diseases and Testing Drugs
Published on: January 27, 2023
Interleukin‑Iβ promotes cartilage degeneration by regulating forkhead box protein O4 and type Ⅱ collagen
Jianxiong Wu1, Hongjun Zhang2, Rulin Deng3
1Department of Emergency Medicine, Sir Run Run Shaw Hospital, Affiliated with The Zhejiang University School of Medicine, Hangzhou, Zhejiang 310085, P.R. China.
Abstract:
Osteoarthritis (OA) is one of the most prevalent pain‑inducing and disabling diseases globally. Aging is a primary contributing factor to the progression of OA. Forkhead box protein O4 (FOXO4) is known to be involved in the cell cycle and apoptosis regulation. The aim of the present study was to investigate the association between FOXO4 expression and chondrocyte degeneration in rats. Chondrocytes were assigned to the control (4‑week‑old rats), natural degeneration (16‑week‑old rats) or induced degeneration (IL‑1β‑treated chondrocytes from 4‑week‑old rats) groups. Immunocytochemical analysis with β‑galactosidase staining revealed a greater number of stained cells present in the natural and induced degeneration groups than in the control group. PCR analysis indicated lower mRNA expression levels of collagen type II α1 chain (Col2α) and higher levels of FOXO4, and western blotting revealed reduced Col2α protein expression levels and significantly elevated FOXO4 levels in the natural and induced degeneration groups, compared with those in the control group. The results of the present study revealed that FOXO4 expression was altered in the natural and induced degeneration groups, and further research and exploration are needed to clarify the underlying mechanism.
Related Concept Videos
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Type IV Collagen of Basal Lamina
A type IV collagen molecule has six alpha chains which can...
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The...
TGF - β Signaling Pathway
Inflammatory Response
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...
Fibril-associated Collagen
For example, the type II collagen fibrils in cartilage have covalently bound type IX fibril-associated collagens at regular intervals. Other types of fibril-associated collagens are...

