Bone Marrow Stromal Cells With Exercise and Thyroid Hormone Effect on Post-Stroke Injuries in Middle-aged Mice

Abstract

Introduction: Based on our previous findings, the treatment of stem cells alone or in combination with thyroid hormone (T₃) and mild exercise could effectively reduce the risk of stroke damage in young mice. However, it is unclear whether this treatment is effective in aged or middle-aged mice. Therefore, this study designed to assess whether combination of Bone Marrow Stromal Cells (BMSCs) with T₃ and mild treadmill exercise can decrease stroke complications in middle-aged mice.

Methods: Under laser Doppler flowmetry monitoring, transient focal cerebral ischemia was produced by right Middle Cerebral Artery Occlusion (MCAO) for 45 min followed by 7 days of reperfusion in middle-aged mice. BMSCs (1×10⁵) were injected into the right cerebral ventricle 24 h after MCAO, followed by daily injection of triiodothyronine (T₃) (20 μg/100 g/d SC) and 6 days of running on a treadmill. Infarct size, neurological function, apoptotic cells and expression levels of Glial Fibrillary Acidic Protein (GFAP) were evaluated 1 week after stroke.

Results: Post-ischemic treatment with BMSCs or with T₃ and or mild treadmill exercise alone or in combination did not significantly change neurological function, infarct size, and apoptotic cells 7 days after ischemia in middle-aged mice (P>0.05). However, the expression of GFAP significantly reduced after treatment with BMSCs and or T₃ (P<0.01).

Conclusion: Our findings indicate that post-stroke treatment BMSCs with exercise and thyroid hormone cannot reverse neuronal damage 7 days after ischemia in middle-aged mice. These findings further support that age is an important variable in stroke treatment.

Keywords: Apoptosis; Bone marrow stromal cells; Cerebral ischemia; Combination; Exercise; Glial fibrillary acidic protein; Mice; Middle-aged; Thyroid hormone.

Figure 1.

Infarct size in different groups Presence of brain damage (A) and microphotographs of cresyl violet staining in sham operated, PBS (control), BMSCs, EX, T₃, BMSCs+T₃, BMSCs+EX and BMSCs+EX+T₃ groups, seven days after MCAO in mice. Values are presented as Mean±SEM.

Figure 2.

Neurological function in different groups Neurological deficit scores (A) and beam balance scores (B) in sham operated, PBS (control), BMSCs, EX, T₃, BMSCs+T₃, BMSCs+EX and BMSCs+EX+T₃ groups, seven days after MCAO in mice. Values are presented as median ± IQR (interquartile range).

Figure 3.

Apoptotic cells in different groups TUNEL staining image (A) and quantitative analysis of number of TUNEL-positive cells (B) in the sham-operated, PBS (control), BMSCs, EX, T₃, BMSCs+T₃, BMSCs+EX and BMSCs+EX+T₃ groups, seven days after MCAO in mice. The number of TUNEL-positive cells (brown) was visualized using a Reichert microscope with a 40× magnification. Values are presented as Mean±SEM.

Figure 4.

GFAP positive cells in different groups Photomicrographs of GFAP-positive cells (A) and quantitative analysis of the number of GFAP-positive cells (B) in the sham-operated, PBS (control), BMSCs, EX, T₃, BMSCs+T₃, BMSCs+EX and BMSCs+EX+T₃ groups, seven days after MCAO in mice. Values are presented as Mean±SEM. *P<0.001 compared to the PBS group. # P<0.001, compared to the sham-operated group. The number of GFAP-stained cells (brown) was visualized using a Reichert microscope with 40× magnification.