Cell counts within the TMJ. Quantitation of (A) ERα-containing cells and (B) the total number of cells within the temporomandibular joint (TMJ). Rats were given a constant infusion of vehicle (No E2) or 17 β-estradiol (E2) using osmotic pumps for one week, and then the TMJ was injected with saline or 30 μg of CFA to produce four treatment groups: No E2/saline, No E2/CFA, E2/saline, E2/CFA. The TMJ was removed en bloc 48 h after TMJ injection, paraffin-embedded, sectioned at 8 μm and immunostained for ERα (Alexa 488 positive) and counterstained with DAPI. The histogram shows the number of ERα-positive stained cells in each of the four tissues (i.e., anterior, disc, retrodiscal and synovial) for each treatment group. Counts included cells with cytoplasmic and nuclear ERα staining. Following staining, the number of DAPI-positive cells in each tissue region was counted for each treatment group. Bars on the histogram were generated from the cell counts of four different animals per treatment group whose values were pooled to give a mean ± SEM. * = p < 0.05.