Effect of Low Birth Weight on Impaired Renal Development and Function and Hypertension in Rat Model

Figures & data

Table 1. Composition of the diets.

	Normaldiet	Low-proteindiet
Ingredients (g/kg)
Maize starch	350.0	530.0
Barley grain	200.0	430.0
Wheat bran	150.0	20.0
Soybean meal	200.0	10.0
Fish meal	100.0	10.0
Nutrient composition of the diets (%)
Protein	21.0	10.0
Fat	3.7	3.5
Carbohydrate	55.0	67.0
Vitamins	0.5	0.5
Minerals	1.0	1.0
Total energy (kcal/kg)	3375.0	3405.0

Table 2. Baseline characteristics of the study groups.

	Pregnantrat number	Total offspringnumber	Mean number of offspringper litter^a	Average birth weightof offspring rats (g)^a	Number of LBWoffspring rats (%)^b	Perinatalmortality (%)
Control group	6	58	10.00 ± 4.72	6.96 ± 0.47	3 (5.17)	1 (1.72)
LBW group	8	90	11.00 ± 2.55	5.99 ± 0.57**	57 (63.33)**	8 (8.89)**

Notes: Analyses of means were by Student’s t-test; analyses of proportions were by chi-square test.

^aValues are presented as means ± SD.

^bLow birth weight was defined as less than average birth weight of offspring rats in the control group minus two standard deviations.

**p < 0.01 compared with control group.

Table 3. Comparison of body weight and right kidney weight of offspring rats between the two groups.

	Time points	Control group (g)	LBW group (g)
Body weight	1 week	16.18 ± 1.09	11.25 ± 4.23**
Kidney weight	1 week	0.10 ± 0.01	0.08 ± 0.01**
Kidney weight/body weight (‰)	1 week	6.52 ± 0.90	6.64 ± 0.69
Body weight	3 weeks	32.24 ± 5.81	27.76 ± 8.40
Kidney weight	3 weeks	0.19 ± 0.03	0.17 ± 0.05
Kidney weight/body weight (‰)	3 weeks	5.92 ± 0.40	6.13 ± 0.45
Body weight	2 months	174.30 ± 9.13	119.26 ± 25.66
Kidney weight	2 months	0.96 ± 0.14	0.61 ± 0.09
Kidney weight/body weight (‰)	2 months	5.53 ± 0.69	5.32 ± 0.65
Body weight	3 months	224.5 ± 10.61	220.13 ± 22.17
Kidney weight	3 months	0.88 ± 0.31	1.05 ± 0.17
Kidney weight/body weight (‰)	3 months	3.98 ± 1.58	4.80 ± 0.67

Notes: Values are presented as means ± SD. Analyses of means were by Student’s t-test.

*p < 0.05 compared with control group, **p < 0.01 compared with control group.

Figure 1. Comparison of the glomerular number between two groups at 2 months.

Notes: Bars represent the total glomerular number of the right kidney (mean ± SD) determined by acid digestion. Analyses of means were by Student’s t-test.

**p < 0.01 compared with control group.

Table 4. Comparison of blood pressure between the two groups at 2 and 3 months.

	Control group (mmHg)	LBW group (mmHg)
2-month-olds	96.28 ± 5.82	120.03 ± 8.31**
3-month-olds	109.75 ± 9.26	127.03 ± 7.13

Notes: Values are presented as means ± SD. Analyses of means were by Student’s t-test.

*p < 0.05 compared with control group, **p<0.01 compared with control group.

Table 5. Comparison of Scr, BUN, Ucr, Ccr, and 24 h urine protein between the two groups.

	Time points	Control group	LBW group
Scr (μmol/L)	3 weeks	21.24 ± 3.14	24.55 ± 4.17
	2 months	26.82 ± 6.30	21.18 ± 2.86
	3 months	27.65 ± 4.05	29.42 ± 4.44
BUN (mmol/L)	3 weeks	6.68 ± 0.96	7.05 ± 1.25
	2 months	7.45 ± 1.15	7.31 ± 1.56
	3 months	7.12 ± 0.77	8.50 ± 1.06
Ucr (μmol/L)	3 weeks	4.69 ± 0.97	4.15 ± 0.71
	2 months	7.20 ± 0.82	5.47 ± 0.66
	3 months	7.01 ± 0.19	4.78 ± 1.19
Ccr (mL/min)	3 weeks	1.35 ± 0.41	0.90 ± 0.09
	2 months	4.33 ± 0.62	3.51 ± 0.54
	3 months	5.09 ± 0.43	3.20 ± 1.22
24 h urine protein (mg/kg day)	3 weeks	24.95 ± 7.15	23.35 ± 3.78
	2 months	93.99 ± 10.01	106.96 ± 6.31
	3 months	79.28 ± 14.26	117.17 ± 10.40**

Notes: Scr, serum creatinine; BUN, blood urea nitrogen; Ucr, urine creatinine; Ccr, creatinine clearance rate;

Values are presented as means ± SD. Analyses of means were by Student’s t-test.

*p < 0.05 compared with control group at the same time point, **p < 0.01 compared with control group at the same time point.

Figure 2. Correlation between blood pressure and glomerular number in the offspring rats at 2 months.

Note: There was a statistically significant correlation between blood pressure and glomerular number of the right kidney determined by acid digestion in both groups at 2 months of age (r = −0.919, p = 0.008).

Figure 3. Correlation between blood pressure and right kidney weight in the offspring rats at 2 months.

Note: There was a statistically significant negative correlation between blood pressure and kidney weight in both groups at 2 months of age (r = −0.697, p = 0.012).