Figure 7

Andrographolide increases skeletal muscle strength in mdx mice. Fibrosis was augmented as explained in the legend of Figure 1. During this period, mice were treated with 1 mg/kg andrographolide or vehicle (intraperitoneal (ip) injections three times per week, six animals per group). (A) Tibialis anterior (TA) muscles were isolated from wild type (WT), vehicle-treated mdx mice, and andrographolide-treated mdx mice to evaluate isometric specific force (mN/mm2) at different stimulation frequencies (pulses per second, pps). (B) Bar graph shows tetanic specific force. Values are represented as percentage of specific isometric force generated by WT muscle (*P < 0.05 relative to WT mice; #P < 0.05 relative to vehicle-treated mdx mice). The recovery score for the twitch force measurement was 54.2%. (C) Bar graph showing twitch force (*P < 0.05 relative to WT mice; #P < 0.05 relative to vehicle-treated mdx mice). The recovery score for the tetanus measurement was 50.3%. (D) Mice were subjected to an exercise challenge on the treadmill at 15 meters/minute for five minutes and the number of set-backs was counted (n = 7, *P < 0.05 relative to WT mice; #P < 0.05 relative to vehicle-treated mdx mice). The recovery score for this measurement was 45.5%.