Figure 4: The protective effect of vitamin D is independent of the transcriptional modulation of TLR-4. The evaluation was performed during the OA induction period for (a)–(d). The gene expression of TLR4 (a), MMP-3 (b), TNF-α (c), and IL-1β (d) from rats in the nV group (□) compared with the sV group (▲) is shown. The gene expression levels were normalized to GAPDH gene expression and presented as the -fold difference in expression. (e) A comparison of the hypertrophy (wideness) of the condyles from rats with 20 days of OA that were supplemented with vitamin D (sV) to that of rats with no supplementation (nV). (f) A morphological comparison between condyles of control rats and rats with 20 days of OA induction treated with vitamin D (sV) and nontreated (nV) by HE stain. The supplementation was performed daily with 4 IU of vitamin D. The results are expressed as pooled data from three independent experiments with 16 to 18 total rats (a–d) or with 6 rats per group (e). The error bars indicate the SEM. A -test with an test was performed to obtain the indicated statistical significance values: , , and . Abbreviations indicate the following treatments: nV (without vitamin supplementation); sV (with vitamin supplementation).