Effects of topical capsaicin combined with moderate exercise on insulin resistance, body weight and oxidative stress in hypoestrogenic obese rats

Abstract

Background: Hypoestrogenic (HE) women are one of the most vulnerable groups for the development of obesity and its complications. Capsaicin and exercise have demonstrated to reduce body weight and to improve insulin sensitivity in different animal models, but it is unknown whether their combination could be useful in HE obese females.

Methods: We investigated whether topical capsaicin, exercise or their combination had better therapeutic effects in an obesity-hypoestrogenism model. Ovariectomized Wistar rats were given a 30% sucrose solution (HE-Obese (HEOb)) or purified water (HE) during 28 weeks ad libitum; four experimental groups per each condition. After shaving the abdominal skin, cold cream vehicle was applied to the Sedentary groups (Sed) and capsaicin cream 0.075% (0.6 mg kg^-1 per day) to the Capsaicin groups (Cap). Exercise (Ex) groups ran on a treadmill every day for 20 min at speeds from 9 to 18 m per min increased every 10 days; combination groups (Cap+Ex) were given topical capsaicin 90 min before exercise. The treatments were performed for 6 weeks, and caloric intake and body weight were monitored. At the end of the experimental protocol, glucose tolerance tests were performed, the animals were killed by decapitation; blood and organs were obtained to perform oxidative profile, histology, biochemical analyses and Western blot.

Results: In HEOb rats, the combined therapy reduced caloric intake, body weight and abdominal fat in a higher proportion than the individual treatments; it also decreased insulin resistance (IR), oxidative stress and pancreatic islet size. It was the only treatment that significantly increased p-AMPK levels in the soleus muscle. In HE rats, topical capsaicin was the only treatment that reduced glucose intolerance and improved the oxidative profile in a higher proportion than the combined therapy or Ex alone.

Conclusions: Capsaicin per se or its combination with moderate exercise could be a useful therapy against complications linked to obesity-IR in HE females.