Effect of betamethasone on the degree of macrophage recruitment and nerve growth factor receptor p75 immunoreaction during recovery of the sciatic nerve after injury: an experimental study in rats.
OBJECTIVE
This study was designed to explain our previous findings of beneficial effects of betamethasone given perioperatively on decreasing the incidence of neurosensory disturbance after sagittal split osteotomy and improving functional recovery after crush injury to rat sciatic nerves. We analysed the pattern of macrophage recruitment and expression of nerve growth factor p75.


METHODS
The sciatic nerve was crushed in each of 42 animals by tying the nerve against a glass rod for 30s. Half the rats were given betamethasone and half were not. The effect of betamethasone was evaluated immunohistochemically in a double blind manner after 2, 7 and 17 days using antibodies against macrophage marker (ED1) and p75.


RESULTS
We found an initial and significant decrease in the number of macrophages recruited after two days in the group treated with betamethasone compared with controls (p=0.001). By 7 days there were significantly more macrophages in the steroid group than in the control group (p=0.001). There was however, a tendency for the number of p75R to be higher in the in the steroid group but the difference was not significant. At 17 days, there were significantly fewer macrophages in the steroid group (p=0.008) than in the control.


CONCLUSIONS
We conclude that the beneficial effect of a moderate perioperative dose of betamethasone on recovery of a nerve is reflected in the recruitment of macrophages but to only a small extent in expression of p75.
Al-Bishri
Awwad
A
Department of Oral and Maxillofacial Surgery, Al-Noor Specialist Hospital, Makkah, Saudi Arabia. albishri@hotmail.com
Forsgren
Sture
S
Al-Thobaiti
Yasser
Y
Sunzel
Bo
B
Rosenquist
Jan
J
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001623:Betamethasone / Q000627:therapeutic use*; D004311:Double-Blind Method; D053331:Ectodysplasins / Q000032:analysis; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D007150:Immunohistochemistry; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D020800:Receptor, Nerve Growth Factor / Q000187:drug effects* / Q000276:immunology; D020127:Recovery of Function / Q000187:drug effects / Q000276:immunology; D012584:Sciatic Nerve / Q000187:drug effects / Q000276:immunology / Q000293:injuries*; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects
D000893:Anti-Inflammatory Agents; D053331:Ectodysplasins; D005938:Glucocorticoids; D020800:Receptor, Nerve Growth Factor; D001623:Betamethasone