TNF and osteoporosis: Interestingly, our results noticed a significant positive correlation between MMP9 tissue expression and inflammatory markers in all studied groups which agree with Zhang et al., [53] who noticed a positive association between MMP9 and TNF-α in osteoporosis in humans, and Singh et al., [54] who showed NF_Kb as an upstream event in CRP-mediated MMP-9 induction in rat models of inflammatory diseases.