Bone healing under experimental anemia in rats

The effects of anemia on different physiological parameters have been the object of permanent study. There are no studies in the literature on the effects of this disorder on the process on bone healing. The aim of the present study was to evaluate, histologically and histomorphometrically, the process of osteogenesis in the post-extraction alvcolus of the lower molar, and in the peri-implant environment of rats. Twenty male Wistar rats (body weight (b.w.): 60 +/- 7 g) were grouped into two experimental sets. The control group (n:10) was given 0.5 mL saline solution i.p. The anemic group (n:10) was injected with 6 mg/100 g of b.w. or 3 mg/100 g b.w. phenylhidrazine, a well known hemolytic agent. Under ketamine-xylazine anesthesia the rats were submitted to extraction of the first lower molars, and to implantation in the tibia in keeping with the [quot ]laminar test[quot ] procedure. Other parameters, i.e. body weight (b.w.), food intake (FI), hematocrit (Htc), and hemoglobinemia (Hb) were monitored every 48 hs. The results showed a reduction in b.w., FI, Htc and Hb in the experimental group. The histological and histomorphometrical data show that the condition of anemia affects osteogenesis quali-quantitatively in the post-extraction alveolus and peri-implant microenvironment. Both bone reparative situations showed that ostegenesis is [quot ]sensitive[quot ] to anemia and/or the associated conditions, causing a delay in bone healing.

Bone healing under experimental anemia in rats.

The effects of anemia on different physiological parameters have been the object of permanent study. There are no studies in the literature on the effects of this disorder on the process on bone healing. The aim of the present study was to evaluate, histologically and histomorphometrically, the process of osteogenesis in the post-extraction alvcolus of the lower molar, and in the peri-implant environment of rats. Twenty male Wistar rats (body weight (b.w.): 60 +/- 7 g) were grouped into two experimental sets. The control group (n:10) was given 0.5 mL saline solution i.p. The anemic group (n:10) was injected with 6 mg/100 g of b.w. or 3 mg/100 g b.w. phenylhidrazine, a well known hemolytic agent. Under ketamine-xylazine anesthesia the rats were submitted to extraction of the first lower molars, and to implantation in the tibia in keeping with the [quot ]laminar test[quot ] procedure. Other parameters, i.e. body weight (b.w.), food intake (FI), hematocrit (Htc), and hemoglobinemia (Hb) were monitored every 48 hs. The results showed a reduction in b.w., FI, Htc and Hb in the experimental group. The histological and histomorphometrical data show that the condition of anemia affects osteogenesis quali-quantitatively in the post-extraction alveolus and peri-implant microenvironment. Both bone reparative situations showed that ostegenesis is [quot ]sensitive[quot ] to anemia and/or the associated conditions, causing a delay in bone healing.

Depressed eruption dental rate in rats with hemodynamically-mediated acute renal failure

The effects of acute renal failure on the impeded (IER) and unimpeded (UER) eruption dental rate and attrition rate (AR) were investigated. Adult female Wistar rats were injected with 125 mg/kg b.w of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (H-ARF). Ten days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of H-ARF. A group of six animals was pair-fed daily and individually with rats of M-Hb groups. Evaluation of renal function, histopathology studies, IER, UER, food intake (FI), AR and body weight gains was performed at different times after the first and second injections, of M-Hb. Treatment induced transient increases in plasma urea concentration and urine volume, and significant depression in urine osmolality, body weight gains, IER, UER and AR. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. The functional values of kidney, histologic findings, IER, UER and AR of the pair-fed rats were not significantly different from control values. The results of the present study indicate that dental eruption rate (IER and UER) is relatively low in uremic rats with kidney tubule lesions and that both parameters are related.

Effect of diphenylhydantoin administration on the growth of the functional components of rat skull

With the purpose of studying the effect of diphenylhydantoin (DPH) administration on the growth of the functional components of the rat skull, male Wistar rats weighing 61.6 + 0.6g were assigned to 1 out of 4 different groups. One of them received saline and was taken as normal control. The others were injected once daily with 25,50 or 100 mg/Kg of b.w. of DPH i.p. for 20 days. Another group of rats was put under a restricted diet (RD) (20 percent of normal intake) for the same time for evaluation of the cranial dimensions. On day 21, the rats were killed by ether overdose and fifteen cranial dimensions were evaluated as peviously described employing Pucciarellis method. The body weight gain of DPH injected rats was up to 20.7 percent lower independently of drug dose. The rats of the RD group showed a similar reduction. The amount of food consumed by DPH rats was 16 percent lower than that consumed by controls independently of drug doses. The concentration of alkaline phosphatase and hemoglobin in rats treated with 50 or 100 mg/kg b.w. of DPH was lower than in controls and RD-animals. However, urea and total calcium in plasma were unchanged in DPH-treated rats as compared to controls. Mean appetite quotient, efficiency of protein and energy utilization did not appear to change in response to the treatment with DPH or maintained under a restricted diet. That cranial dimensions of rats, injected with 25mg/kg b.w. of DPH were not statistically different from those of the control and RD-groups. When the dose of DPH injected was 50 mg/kg b.w. the neurocranial width an height and the spachnocranial length were significantly lower than controls and RD-values. Moreover, all the dimensions corresponding to neurocranium and splachnocranium (width, height and length) of the rats injected with 100 mg/kg b.w. of DPH were significantly lower than those of control and RD-groups. The disharmonius growth of the skull do not appear to be dependent on suboptimal energy intake, efficiency of protein, energy utilization renal failure and anemia. (AU)

Suppressive effect of acetylsalicylic acid on erythropoietin-responsive cells in mice.

The time-response curve for RBC-59Fe uptake following i.p. injections of 3 doses of 5 mg of acetylsalicylic acid (ASA) at 4 hour interval into normal, nonpolycythemic mice, shows a maximal depression (35

of normal) at 3 days after ASA with return to almost normal values by 7 days. The effect is dose-related, showing a plateau with doses of ASA above 5 mg/4 hr. The shape of the time-response curve indicates that the more mature cells in the erythron are not affected by ASA and that the major effect of the drug must be on earlier erythroid cells. Administration of ASA prior to administration of erythropoietin (Epo) into post-hypoxic polycythemic mice depresses the incorporation of 59Fe into erythrocytes. The depression of radioiron uptake is similar when ASA is given prior to or simultaneously with Epo. When ASA is given 24 hr after injection of Epo, suppression is less marked. These results suggest a suppressive effect of the drug on the erythropoietin-responsive cells (ERC).

Depressed eruption dental rate in rats with hemodynamically-mediated acute renal failure.

The effects of acute renal failure on the impeded (IER) and unimpeded (UER) eruption dental rate and attrition rate (AR) were investigated. Adult female Wistar rats were injected with 125 mg/kg b.w of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (H-ARF). Ten days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of H-ARF. A group of six animals was pair-fed daily and individually with rats of M-Hb groups. Evaluation of renal function, histopathology studies, IER, UER, food intake (FI), AR and body weight gains was performed at different times after the first and second injections, of M-Hb. Treatment induced transient increases in plasma urea concentration and urine volume, and significant depression in urine osmolality, body weight gains, IER, UER and AR. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. The functional values of kidney, histologic findings, IER, UER and AR of the pair-fed rats were not significantly different from control values. The results of the present study indicate that dental eruption rate (IER and UER) is relatively low in uremic rats with kidney tubule lesions and that both parameters are related.

Depressed plasma erythropoietin levels in rats with hemodynamically-mediated acute renal failure.

Adult female Wistar rats were injected with 125 mg/kg b.w. of human methemoglobin (M-Hb) in order to induce a first episode of hemodynamically-mediated acute renal failure (HMARF). Eleven days after the injection of M-Hb, other groups of rats received another equal dose of the drug in order to induce a second episode of HMARF. Evaluation of renal function, histopathology studies, and determinations of plasma and kidney erythropoietin (Epo) titers by radioimmunoassay in normoxic and hypoxic conditions were performed 1, 2, 3, 5 and 10 days after M-Hb administration. Treatment induced transient increases in plasma urea concentration, fractional sodium excretion, and urine volume, and significant depression in urine osmolality. In every case, the maximal effect of the first injection of M-Hb on the individual parameters was always greater than that of the second injection, and observed on the 5th post-injection day. Histologic sections showed interstitial cellular infiltration, desquamation of the proximal tubular epithelium and collapse or dilation of the tubular lumen. Treatment with M-Hb depressed Epo titers in both kidney homogenates and plasma in normoxic as well as hypoxic rats. Here again, the effect of the first injection of the drug was higher than that of the second one. These observations indicate that there is a negative correlation between kidney tubule injury and Epo production in normoxic and hypoxic conditions. The findings give support to the concept that Epo production is related to proximal tubular function.