The Influence Of Vitamin D Intervention To Blood Pressure In Spontaneously Hypertensive Rats

Objective:To explore the influence of long-term regular vitamin D intervention onblood pressure in spontaneously hypertensive rats. Methods:20spontaneouslyhypertensive rats were randomly divided into two groups. The experimental group recivedvitamin D3preparation3μg/kg dissolved in0.5ml propylene glycol by intraperitonealinjection (twice a week) for three months; the control group was given the equal volumeof propylene glycol alone，twice a week for12weeks. To monitor the change of bloodpressure of rats during the experiment every week.12weeks after, all of rats weresacrificed, and Serum was collected.Serum25(OH)D3, calcium, IL-6,MMP-9，renninparathyroid hormone, renin, angiotensin II and aldosterone concentration were detected byEnzyme-linked immunosorbent. Collect the heart and kidneys, calculate the kidney/bodyweight ratio and heart/body weight ratio.To explore renin and renin receptor mRNAexpression levels in kidney between the two groups by RT-PCR. Renin receptor’sexpression in kidney and heart was examined by immunohistochemical and computerimage analysis. Pathological changes was examined by HE staining. Results: The bloodpressure of experimental group was lower than that in control group[(156.4±8.8)vs(170.8±8.4)mmHg,P＜0.05]. Serum25(OH) D3, calcium concentration in experimentalgroup were higher than that in control group[(104.19±0.02)vs(74.22±0.03)ng/ml，(2.26±0.12)vs(2.11±0.19)mmol/l，P＜0.05].IL-6、MMP-9were lower than control group[(9.80±3.62)vs(35.56±25.1）,(56.57±16.03)vs(98.78±19.79)，P<0.05]。The concentrationof PTH was lower （[268.98±25.09）vs（324.24±39.68），P＜0.05]。Renin and angiotensinII level were lower than those in control group [(214.14±24.04)vs(248.845±25.99)pg/ml，(142.49±37.51)vs(184.84±35.69)pg/ml，P＜0.05]。The heart/body weightratio in the experimental group is less than that in control group (P <0.05). RT-PCR resultsshowed that there was significant difference of renin mRNA expression in kidney in the two groups, which expressed in the experimental group more than that in controlgroup[(0.133±0.007) vs (0.316±0.012), P＜0.05]. There was no difference of reninreceptor mRNA expression between the two groups[(0.366±0.013)vs (0.400±0.017),P＞0.05]. It found that renin receptor was widely distributed by Immunohistochemical, butthere was no difference in kidney and heart in the two groups[(83166±4708)vs (100833±9703)；(89666±7004)vs (93000±4939)，P＞0.05]. HE staining displayed there washypertensive pathological changes in control group, but it was not obvious in theexperimental group. Conclusion: Vitamin D plays a protective role in the blood pressureby three factors as PTH、renin-angiotensin system and inflammation.