Fig. 1

Effects of sericin on the testicular injury of mice induced by photoperiod. (I) The body weight of mice measured every three days. (II) Body weight in the fifth week, testes weight, and testes index expressed as the ratio of testicular weight to body weight. (III) Histopathology with H&E staining (200 and 400) of the testicular section on mice after treatment for five weeks. (A) Normal seminiferous tubule morphology, (B) affected testicular tissue after short photoperiod, (C) Sericin testicular tissue after short photoperiod showing normal seminiferous tubule morphology: few numbers of sperms in one seminiferous tubule, (D) Affected testicular tissue after long photoperiod, (E) Sericin testicular tissue after long photoperiod showing normal seminiferous tubule morphology. (IV) Morphometric analysis of cross-sectional area of seminiferous tubule, lumen area and seminiferous epithelium area

Abbreviations: CG – control group, SPG-P – short photoperiod group placebo, SPG-S – short photoperiod group sericin-treated, LPG-P – long photoperiod group placebo, LPG-S – long photoperiod group sericin-treated. S – seminiferous tubules, BM – basement membrane, SG – spermatogonia, SP – spermatocytes, Sd – spermatids, Sz – spermatozoa, Sc – Sertoli cells, Lc – Leydig cells, * – enlarged intercellular spaces, normal arrow – degenerated seminiferous tubule, curved arrow – degenerate basement membrane, arrowhead – degenerate Leydig cells. The same letters denote homogenous groups (equal/different slope model; ANOVA, LSD test, p < 0.05)