Effects of inflammatory pain on inflammatory reaction and expressions of TNF-α and MCP-1 in peripheral tissue of mice / 西安交通大学学报(医学版)

ABSTRACT

Objective: To investigate the effects of inflammatory pain on local tissue structure, inflammatory reaction and expression levels of TNF-α and MCP-1 in formaldehyde-induced inflammatory pain in mice. Methods: Sixty-four adult male mice were randomly divided into NS group (40 μL of saline injected into the wrist of right forelimb), FCOH group (50 mL/L formaldehyde of 40 μL injected into the wrist of right forelimb), L group (5 μg/mL lidocaine of 0.3 mL for brachial plexus anesthesia) and FCOH+L group. Some of the tissue samples were collected at 48 h after formaldehyde modeling to observe the infiltration of inflammatory cells by HE staining. The rest were used to assess the expression levels of TNF-α and MCP-1 by Western blot. Results: Compared with NS group, FCOH group showed peak inflammatory response at 24 h (thickness of injection sites 1.73 mm vs. 4.02 mm, temperature 37 ℃ vs. 38.3 ℃, P<0.05). However, FCOH+L group showed intense inflammatory responses at 48 h (thickness of injection sites 1.68 mm vs. 5.10 mm, temperature 37 ℃ vs. 38.5 ℃, P<0.05). Furthermore, after 48 h FCOH group had a lower degree of infiltration of inflammatory cells and higher expression levels of TNF-α and MCP-1 than those in FCOH+L group (P<0.05). Conclusion: Inflammatory pain plays a significant role in the healing process of injured issues by facilitating the local inflammation and affecting the duration. The expression levels of TNF-α and MCP-1 in local tissues decrease by interrupting the transmission of pain.