RESUMO
AIM: To study the effects of estrogen therapy on the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and perlecan in the vascular wall. METHODS: Twenty 180-day-old Wistar rats were castrated and treated 1 week later for a period of 4 weeks with one of the following: (1) placebo; (2) 0.5 µg/day estradiol benzoate (E(2)B); (3) 5 µg/day E(2)B; (4) 50 µg/day E(2)B. A fifth group consisted of rats that had not been castrated. Following treatment, expression of MMP-2 and MMP-9 mRNA (MMP-2([RNA]) and MMP-9([RNA]), respectively) was analyzed by real-time PCR, and expression of MMP-2 (MMP-2([IH])), MMP-9 (MMP-9([IH])) and perlecan was quantified by immunohistochemistry, in carotid walls. RESULTS: There were no differences among castrated groups for MMP-2([RNA]) (p = 0.1969) and for MMP-9([RNA]) (p = 0.1828); however, a correlation was observed between E(2)B dose and MMP-9([RNA]) levels (r = 0.471, p = 0.018). Differences among groups were observed for MMP-2([IH]), MMP-9([IH]) and perlecan (p < 0.0001), wherein higher levels were observed in animals treated with estrogen therapy, correlating with E(2)B doses in the case of MMP-9 (r = 0.441, p = 0.026) and perlecan (r = 0.574, p = 0.005). CONCLUSIONS: Estrogen therapy correlates with higher levels of MMP-2, MMP-9 and perlecan in the extracellular matrix of carotid walls in castrated rats, in a dose-dependent manner. There was a dose-response effect of E(2)B on the expression of MMP-9 mRNA and, possibly, MMP-2 mRNA.
Assuntos
Artérias Carótidas/metabolismo , Estradiol/análogos & derivados , Estrogênios/farmacologia , Proteoglicanas de Heparan Sulfato/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Análise de Variância , Animais , Artérias Carótidas/enzimologia , Relação Dose-Resposta a Droga , Estradiol/administração & dosagem , Estradiol/farmacologia , Estrogênios/administração & dosagem , Feminino , Expressão Gênica/efeitos dos fármacos , Proteoglicanas de Heparan Sulfato/genética , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Ovariectomia , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Estatísticas não ParamétricasRESUMO
BACKGROUND: Malignant melanoma (MM) is a very aggressive tumour. Although surgical excision of MM in the early stages has a very good prognosis, it often fails to completely inhibit tumour progression. Methylene blue photodynamic therapy (MB-PDT) is a technique that induces tissue damage by reactive oxygen species (ROS). AIM: To investigate the efficacy of and potential use of MB-PDT in restraining the aggressiveness of MM by analysing levels of proliferating cell nuclear antigen (PCNA) and heparanase (HPSE, a molecular marker of cell invasion) in a mouse model. METHODS: Expression of PCNA and two HPSE isoforms were analysed using immunohistochemistry (IHC) after MB-PDT in mice. Tumour volume and weight were also measured. RESULTS: Two treatments with MB-PDT promoted a decrease of 99% decrease in tumour volume and 75% in tumour weight compared with untreated mice (P < 0.05). Using IHC, a decrease in expression of 75% for PCNA and 95% for both HPSE isoforms (P < 0.05) was found. CONCLUSION: MB-PDT is a cheap and efficient method of decreasing MM volume and thus disease progression. This reduction is mediated by downregulation of PCNA and heparanases.