Opuntia cladode powders inhibit adipogenesis in 3 T3-F442A adipocytes and a high-fat-diet rat model by modifying metabolic parameters and favouring faecal fat excretion

Abstract

Background: Obesity is a major public health concern worldwide. A sedentary life and a nutritional transition to processed foods and high-calorie diets are contributing factors to obesity. The demand for nutraceutical foods, such as herbal weight-loss products, which offer the potential to counteract obesity, has consequently increased. We hypothesised that Opuntia cladodes consumption could assist weight management in an obesity prevention context.

Methods: This study was designed to explore the anti-adipogenic effects of lyophilised Opuntia cladode powders (OCP) in an in vitro cellular model for adipocyte differentiation and an in vivo high-fat-diet (HFD)-induced obesity rat model. Two OCP were tested, one from wild species O. streptacantha and the second from the most known species O. ficus-indica.

Results: Pre-adipocytes 3 T3-F442A were treated by OCP during the differentiation process by insulin. OCP treatment impaired the differentiation in adipocytes, as supported by the decreased triglyceride content and a low glucose uptake, which remained comparable to that observed in undifferentiated controls, suggesting that an anti-adipogenic effect was exerted by OCP. Sprague-Dawley rats were fed with a normal or HFD, supplemented or not with OCP for 8 weeks. OCP treatment slightly reduced body weight gain, liver and abdominal fat weights, improved some obesity-related metabolic parameters and increased triglyceride excretion in the faeces. Taken together, these results showed that OCP might contribute to reduce adipogenesis and fat storage in a HFD context, notably by promoting the faecal excretion of fats.

Conclusions: Opuntia cladodes may be used as a dietary supplement or potential therapeutic agent in diet-based therapies for weight management to prevent obesity.

Keywords: 3T3-F442A adipocytes; Anti-obesity; Faecal fat excretion; Opuntia; Rat high-fat diet.

Fig. 1

Effects of OCP on cell viability, triglyceride content and glucose uptake in 3 T3-F442A differentiating adipocytes. 3 T3-F442A pre-adipocytes were grown for 10 days in culture medium renewed every 2–3 days. Opuntia cladode powders (OCP), O. streptacantha (OSC) and O. ficus-indica (OFI) were diluted directly in the culture medium (concentrations used were 1, 10, 100 μg/mL). a, b Cell viability was assessed in pre-adipocytes (left panel) and differentiated adipocytes (induced by 50 nM insulin; right panel) using the MTT assay after treatment with OSC (a); OFI (b). Graphs show the average values of three independent experiments. Results are expressed as mean percentage of the control (cells without OCP) in non-differentiated adipocytes. Statistical analyses involved ANOVA, followed by Newman–Keuls post hoc test. (c, d) TG content of 3 T3-F442A adipocytes was evaluated in pre-adipocytes (left panels) and differentiated adipocytes (right panels) treated with OSC (c); OFI(d). Data represent the mean percentage levels of the control (without OCP) in non-differentiated adipocytes normalised to protein content. Statistical analyses involved ANOVA, followed by Newman–Keuls post hoc test. **p < 0.01, ***p < 0.005 indicates significant difference from control without insulin and treatment; §§ p < 0.01 indicates significant difference between groups in insulin-treated cells. (e, f) Insulin-stimulated uptake of glucose in 3 T3-F442A adipocytes and effect of OCP. Glucose uptake was evaluated in pre-adipocytes (left panels) and differentiated adipocytes (right panels), with/without OCP treatment with OSC (c);OFI (d). Data are the mean percentage levels of the control (without OCP) in non-differentiated adipocytes normalised to protein content. Cytochalasin (cyto) 10 μM, was used as the negative control for glucose uptake. Statistical analyses involved ANOVA, followed by Newman–Keuls post hoc test. ^$p < 0.005 significantly different from all groups; **p < 0.01, *p < 0.05 significant difference from control without insulin and treatment; ^§§p < 0.01, ^§§§p < 0.005 indicates significant difference between groups in insulin-treated cells

Fig. 2

Effects of OCP on body mass. The effects of Opuntia cladode powders (OCP) were evaluated in HFD-fed rats supplemented with 0.5% O. streptacantha and O. ficus-indica, respectively (F-OSC, F-OFI), compared with OCP-untreated controls (F). Group SD received a standard diet. a Body mass evolution was recorded weekly over 8 weeks. An average of the body weight of each group is expressed by mean ± SEM. b The body mass gain was calculated for each animal as the difference of its body mass between the start (day 0) and end (day 60) of the experiment. Data represent mean ± SEM from each group. c The food intake was recorded for each animal over 8 weeks. All data represent mean ± SEM. Each group was composed of 10 rats. Statistical analyses involved ANOVA, followed by Newman–Keuls post hoc test. **p < 0.01, ***p < 0.005 indicates significant difference from group SD; ^§p < 0.05 denotes significant difference from group F

Fig. 3

Effects of Opuntia cladode powders (OCP) supplementation on relative abdominal fat mass (a) and liver mass (b). Data represent mean ± SEM. Statistical analysis involved ANOVA, followed by Newman–Keuls post hoc test. *p < 0.05, **p < 0.01, ***p < 0.005 indicates significant difference from the group fed the standard diet (SD)

Fig. 4

Effect of OCP supplementation on various biological parameters in rat serum. Rats were fed with (F) or without (SD) a high-fat diet, supplemented with Opuntia cladode powders (OCP) from O. streptacantha and O. ficus-indica, respectively (F-OSC, F-OFI). a Adiponectin (μg/mL); (b) leptin (pg/mL); (c) triglycerides (mM); (d) glucose (mM); (e) insulin (pg/mL). All data represent mean ± SEM. Each group was composed of 10 rats. Statistical analyses involved ANOVA, followed by Newman–Keuls post hoc test. *p < 0.05, **p < 0.01, ***p < 0.005 indicates significant difference from group SD;^§p < 0.05, ^§§p < 0.01 significant difference from group F

Fig. 5

Triglyceride content in liver (a) and faeces (b). Rats were fed with (F) or without (SD) a high-fat diet, supplemented with Opuntia cladode powders (OCP) from O. streptacanthaand O. ficus-indica, respectively (F-OSC, F-OFI). Triglyceride concentrations were reported relative to liver or faeces weight. Data represent mean ± SEM. Statistical analysis involved ANOVA, followed by Newman–Keuls post hoc test. *p < 0.05 indicates significant difference from group SD