Objective To analyze the characteristics and significance of
matrix metalloproteinase-9 (
MMP-9) expression in the pathophysiological processes of
tuberculous meningitis in
mice.
Methods Sixteen
mice were intracerebroventricularly injected with H37RV
suspension as the model group.Meanwhile,the other 16
mice were injected with 0.9%
sodium chloride solution as the
control group.Thirty days later,all
mice were decapitated and the
brain tissue were respectively used to for
Mycobacterium tuberculosis (M.
tuberculosis) incubation,pathological changes
observation,
MMP-9 activity
detection by zymography,
blood-
brain-
barrier permeability and moisture content
detection,and
immunofluorescence stain of
MMP-9,
glial fibrillary acidic protein (GFAP) and
integrin αM (OX-42).The t test was used to compare the differences between the two groups.Results Every experimental
mouse was injected with (1.271±0.111) × 106
colony-forming units (cfu) M.
tuberculosis.Thirty days later,the amount of M.
tuberculosis in
brain tissue homogenates was (4.900± 1.407) × 104 cfu/mL,and the
hematoxylin and
eosin staining showed
dilatation of subarachnoid and ventricular and infiltration of a large number of inflammatory
cells.The cumulative absorbance (A) of
MMP-9 bands of
brain tissue was 47 821 ± 19 932 in the model group and 10 082 ± 3 544 in the
control group.The difference was statistically significant (t =3.728,P=0.010).The
evans blue (EB) content of
brain tissue was (11.8 ± 3.6) μg/g in model group and (4.7 ±3.4) μg/g in
control group.The difference was statistically significant (t=2.887,P=0.028).The moisture of
brain tissue was 0.849±0.035 in model group and 0.775±0.037 in
control group.The difference was statistically significant (t=2.925,P=0.026).The
immunofluorescence staining showed that the infected
brain tissue expressed high degrees of
MMP-9,GFAP and OX-42.And
MMP-9 was overlapped with both GFAP and OX-42 obviously.Conclusions The activity of
MMP-9 is significantly enhanced in
brain tissue of
mice suffering from
tuberculous meningitis and participates in
blood-brain barrier damage,
tissue edema and inflammatory
cells exudation.
Microglia cells-
astrocytes network is involved in the
secretion of
MMP-9.