Fig. 1

Effect of resveratrol/curcumin on IL-1β- or U0126-induced degenerative changes and apoptosis in primary chondrocytes. a Electron microscopic demonstration of an untreated chondrocyte (c) containing smooth surface, large nucleus with much loosely packed, functionally active euchromatin and little condensed, functionally inactive heterochromatin, numerous cavities of rough endoplasmic reticulum (A). Treatment with 10 ng/ml IL-1β (B–E) or 1 μM U0126 (F–I) for 1, 12, 24, 48 h resulted in nuclear changes with peripheral segregation and aggregation of chromatin into dense areas along the nuclear membrane, swelling and dilatations of cell organelles (mitochondria and endoplasmic reticulum) (C, G, Inset) and membrane blebbing. Longer incubations of 24–48 h led to the formation of apoptotic bodies and cell lysis. However, pre-treatment with 10 μM resveratrol (J–M) or 10 μM curcumin (N–Q) alone or with 10 μM resveratrol and 10 μM curcumin (R–U) followed by co-treatment with U0126 or IL-1β inhibited the adverse effects of IL-1β (data not shown) or U0126 (J–U). After 48-h treatment, chondrocytes demonstrate large, flattened cells with numerous microvilli-like processes, mitochondria and endoplasmic reticulum comparable to control cultures. b To quantify apoptosis in these cultures, 100 cells from 20 microscopic fields were counted. The number of apoptotic cells was highest in cultures stimulated with IL-1β or U0126 alone. However, pre-treatment of the chondrocytes with resveratrol, curcumin or a combination of the two phytochemicals significantly decreased the number of IL-1β- or U0126-induced apoptotic cells compared to each chemical by itself (asterisk)