Correlation of MMP₁ and TIMP₁ expression with pituitary adenoma fibrosis

Objective To explore the correlation of matrix metalloproteinase-1 (MMP₁) and tissue inhibitor of metalloproteinase-1 (TIMP₁) with pituitary adenoma fibrosis. Methods Thirty-eight pituitary adenoma specimens were divided into fibrous group (6 patients) and non-fibrous group (32 patients). MMP₁ and TIMP₁ expression was detected by RT-PCR and immunohistochemistry. The collagen content was determined by Sirius scarlet staining. Results In fibrous and non-fibrous group: (1) the collagen content was 20.95 ± 8.42% and 7.98 ± 5.18% respectively, and there was a statistical significance (P < 0.01). (2) The expression of MMP₁mRNA was 0.47 ± 0.40 and 0.59 ± 0.54 respectively and its protein expression was 0.12 ± 0.09 and 0.13 ± 0.09 respectively, and there was no statistical significance (P > 0.05). Their expression was not related to collagen content (P > 0.05). (3) The expression of TIMP₁mRNA was 1.61 ± 1.09 and 0.79 ± 0.59 respectively and its protein expression was 0.58 ± 0.11 and 0.32 ± 0.18 respectively, and there was a statistical significance (P < 0.01). Their expression was related to collagen content (P < 0.01). Conclusion The pathological features of pituitary adenoma fibrosis are excessive collagen deposition. High expression of TIMP₁ may be an important cause.