Table 2 Criteria for the grading of embryos into normal, mild and severe phenotypes at 48 hpf
Morphological endpoints | Normal | Mild | Severe |
|---|---|---|---|
Head | Flexed | Straight | Extended |
Tail | Properly detached and straight | Normal length and curved | Short length and curved |
Anterior-posterior (AP) axis | Normal head and tail position | AP axis mildly disrupted | AP axis not well formed |
Yolk | Transparent | Bigger than control and/or deformed | At least double than size of control with necrosis |
Heart beat | Regular with synchronous contractions | Slow or fast | Slow or fast with asynchronous contractions |
Pericardial edema | Absent | Mild | Moderate to big |
Blood circulation | Regular and continuous flow | Irregular and/or decreased flow | Absent flow |
Somites | V-shaped | C-shaped | Straight |
Chorda | Smooth, straight and well demarcated border | Tortuous border with bulging | Tortuous and not well demarcated border |