Spirulina ameliorates arsenic induced reproductive toxicity in male rats

Abstract

Spirulina (Spirulina platensis), has numerous health benefits including antioxidant, immunomodulatory, and anti-inflammatory activities, works against heavy metal toxicity, and is often used as a food supplement in human, animals, birds and fishes. This study aimed to evaluate the protective ability of the dietary spirulina against the toxic effects of inorganic arsenic (iAs) on male reproductive parameters in rats. Seventy-two mature Long-Evans male rats, dividing into six groups (T0, T1, T2, T3, T4 and T5) (12 rats/group) were included in this study. The T3, T4 and T5 group rats were treated with three consecutive doses (1.0 g, 1.5 g and 2.0 g/kg feed) of spirulina in feed along with 3.0 mg NaAsO₂/kg body weight (BW) in drinking water (DW) daily for 90 days. Each rat of group T1 received NaAsO₂ (3.0 mg/kg BW) in DW, and those of T2 group were fed with spirulina (2.0 g/kg feed) daily for 90 days. The rats of group T0 served as the control with normal feed and water. Total arsenic (tAs) contents, reproductive parameters (testicular weight, sperm motility and morphology), and histological changes in the testicles were evaluated in these rats. Arsenic dosing significantly (p=0.003, Kruskal-Wallis test) increased the tAs contents in the testicles, decreased testes weight, sperm morphology and motility compared to the controls. The effect of arsenic dosing was also evidenced by the histological changes like decreased germinal layers in the seminiferous tubules of the treated rats. Moreover, dietary spirulina (2.0 g/kg feed) supplementation significantly (p=0.011, Kruskal-Wallis test) lowered tAs contents in testicles and increases testes weights, sperm motility and morphology. Therefore, spirulina can be used as an effective dietary supplement to ameliorate the adverse effects of arsenic induced reproductive toxicities. However, further study is required to elucidate the underlying molecular mechanisms of reduction of arsenic induced reproductive toxicity by spirulina.

Keywords: arsenic; reproductive parameters and rats; spirulina; toxicity.

Figure 1. Photographs of rat testes and epididymis. (A) Rate testis with epididymis; (B) rat testis after incising the epididymis; (C) right testis without epididymis and (D) left testis without epididymis.

Figure 2. Sperm morphology of trial rats on sampling days. (A) Photograph of rat spermatozoa ×200; (B) rat sperm with detached tail in trial rats on sampling days ×400; (C) rat sperms with coiled tail in trial rats on sampling days ×400; (D) rat sperms with bent tail in trial rats on sampling days ×400. Arrow indicate the specific sperm abnormality.

Figure 3. Hematoxylin and eosin-stained histopathological changes of testis in experimental and control groups. (A) Histopathological changes in testicles of control rat x1000; (B) histopathological changes in testicles of iAs induced control rats x1000; Green arrows indicate normal seminiferous tubules and black arrows indicate seminiferous tubules with increased luminal areas and thinner germinal layers; and (C) percent of the seminiferous tubules with increased luminal areas and thinner germinal layers in the testicle of trial rats on sampling days. Number of animals, n= 12/group.

Figure 4. Summary of findings. Left panel: arsenic (As) induces reproductive toxicities in male rats by increasing total As contents and decreasing testicular weights and number of germinal epithelial layers of seminiferous tubules. As also increases number of abnormal sperm and reduces sperm motility. Right panel: Spirulina mitigates As-induced reproductive toxicities in male rats. Blue arrows (↑) indicate increased while black arrows (↓) indicate decreased.