Fig. 3
a A. Healthy group showing synovial membrane is covered by two layers of thin flat intimal cells (↑). The subintimal connective tissue consists of fat cells (▲) with few blood capillaries (*). B. Group II 2 weeks after osteoarthritis induction showing thickened synovial membrane with stratified cell layers (↑), and subintimal connective tissue infiltrated extensively by inflammatory cells (▲) with many dilated congested blood vessels (*). (H&E, X400). b A. Group II at 1 month showing thickened synovial membrane with stratified layers of intimal lining (↑), and subintimal connective tissue with thick collagen bundles (↑↑), inflammatory cells infiltrate (▲) and dilated congested blood capillaries (*). B. Group III at 1 month showing synovial membrane with relatively thin intima consists of 2 layers of flat cells (↑). Notice the subintimal connective tissue is formed of irregularly arranged thick collagen bundles (↑↑) and scattered few inflammatory cells (▲). C. Group II at 2 months showing synovial membrane with moderately thin intima (↑), but the subintimal connective tissue still contains thick collagen bundles (↑↑), mononuclear cellular infiltrate (▲) with dilated blood capillaries (*). D. Group III at 2 months showing synovial membrane with thin intima (↑). The subintimal connective tissue is formed of irregularly arranged thin collagen bundles (↑↑) and scattered few mononuclear cells (▲) with thin-walled blood capillaries (*). (H&E, X400)